{"id":3034,"date":"2022-02-20T22:04:17","date_gmt":"2022-02-20T14:04:17","guid":{"rendered":"https:\/\/egonlin.com\/?p=3034"},"modified":"2022-02-20T22:04:17","modified_gmt":"2022-02-20T14:04:17","slug":"%e7%ac%ac%e4%ba%8c%e8%8a%82%ef%bc%9akd%e6%a0%91","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=3034","title":{"rendered":"\u7b2c\u4e8c\u8282\uff1akd\u6811"},"content":{"rendered":"<h1>kd\u6811<\/h1>\n<p>&emsp;&emsp;k\u8fd1\u90bb\u7b97\u6cd5\u4e2d\u8bb2\u5230\u5b83\u6709\u4e00\u4e2a\u8f83\u4e3a\u81f4\u547d\u7684\u7f3a\u70b9\u5c31\u662f\u6bcf\u4e2a\u5b9e\u4f8b\u5230\u672a\u6765\u65b0\u6570\u636e\u4e4b\u95f4\u90fd\u9700\u8981\u8ba1\u7b97\u4e00\u6b21\u8ddd\u79bb\uff0c\u5982\u679c\u5b9e\u4f8b\u6570\u8d8b\u4e8e\u65e0\u7a77\uff0c\u90a3\u4e48\u8ba1\u7b97\u91cf\u662f\u5f88\u5e9e\u5927\u7684\u3002\u4f46\u662f\u6211\u4eec\u8981\u77e5\u9053\u7684\u662f\u8ba1\u7b97\u8ddd\u79bb\u662f\u4e3a\u4e86\u627e\u5230\u8ddd\u79bb\u76ee\u6807\u70b9\u6700\u8fd1\u7684$k$\u4e2a\u5b9e\u4f8b\uff0c\u90a3\u4e48\u662f\u4e0d\u662f\u6709\u53e6\u5916\u4e00\u79cd\u66f4\u597d\u7684\u65b9\u6cd5\uff0c\u80fd\u591f\u66f4\u5feb\u901f\u627e\u5230\u8fd9$k$\u4e2a\u6700\u8fd1\u7684\u5b9e\u4f8b\u5462\uff1f\u7531\u6b64kd\u6811\u88ab\u53d1\u660e\u4e86\u51fa\u6765\u3002<\/p>\n<p>&emsp;&emsp;kd\u6811(k-dimensional tree)\u7b80\u5355\u800c\u8a00\u5c31\u662f$k$\u4e2a\u7279\u5f81\u7ef4\u5ea6\u7684\u4e8c\u53c9\u6811\uff0c\u8981\u6ce8\u610f\u8fd9\u91cc\u7684$k$\u503c\u548ck\u8fd1\u90bb\u7b97\u6cd5\u4e2d\u7684$k$\u503c\u4e0d\u540c\u3002<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2021\/08\/05-03-\u597d\u8822\u5440-1.jpg'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2021\/08\/05-03-\u597d\u8822\u5440-1.jpg\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h1>kd\u6811\u5b66\u4e60\u76ee\u6807<\/h1>\n<ol>\n<li>kd\u6811\u7684\u6784\u9020\u4e0e\u641c\u7d22<\/li>\n<li>kd\u6811\u6d41\u7a0b<\/li>\n<li>kd\u6811\u4f18\u7f3a\u70b9<\/li>\n<\/ol>\n<h1>kd\u6811\u5f15\u5165<\/h1>\n<pre><code class=\"language-python\"># kd\u6811\u5f15\u5165\u56fe\u4f8b\nimport numpy as np\nimport matplotlib.pyplot as plt\nfrom matplotlib.font_manager import FontProperties\n%matplotlib inline\nfont = FontProperties(fname=&#039;\/Library\/Fonts\/Heiti.ttc&#039;)\n\n# \u6d4b\u8bd5\u70b9\nplt.scatter(5, 6, marker=&#039;s&#039;, c=&#039;k&#039;, s=50)\nplt.text(5, 5, s=&#039;\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b(5,6)&#039;, fontproperties=font, ha=&#039;center&#039;)\n\n# \u751f\u6210\u52a8\u4f5c\u7247\nnp.random.seed(1)\naction_x1 = np.random.randint(1, 7, 15)\naction_x2 = np.random.randint(8, 17, 15)\nplt.scatter(action_x1, action_x2, marker=&#039;o&#039;, s=30, c=&#039;r&#039;, label=&#039;\u52a8\u4f5c\u7247&#039;)\n\n# \u751f\u6210\u7231\u60c5\u7247\nromance_x1 = np.random.randint(8, 17, 15)\nromance_x2 = np.random.randint(1, 7, 15)\nplt.scatter(romance_x1, romance_x2, marker=&#039;x&#039;, s=30, c=&#039;g&#039;, label=&#039;\u7231\u60c5\u7247&#039;)\n\n# \u6d4b\u8bd5\u6587\u672c\u6807\u8bb0\nplt.text(4, 11, s=&#039;A&#039;, ha=&#039;center&#039;)\nplt.text(5, 7, s=&#039;B&#039;, ha=&#039;center&#039;)\nplt.text(1, 14, s=&#039;C&#039;, ha=&#039;center&#039;)\n\nplt.xlim(0, 18)\nplt.ylim(0, 18)\nplt.xlabel(&#039;\u63a5\u543b\u955c\u5934(\u6b21)&#039;, fontproperties=font)\nplt.ylabel(&#039;\u6253\u6597\u573a\u666f(\u6b21)&#039;, fontproperties=font)\nplt.title(&#039;kd\u6811\u5f15\u5165\u56fe\u4f8b&#039;, fontproperties=font, fontsize=20)\nplt.legend(prop=font)\nplt.show()<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_5_0.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_5_0.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>&emsp;&emsp;\u8fd9\u91cc\u5c06\u7ee7\u7eed\u6cbf\u7528k\u8fd1\u90bb\u7b97\u6cd5\u7684\u4f8b\u5b50\u3002<\/p>\n<p>&emsp;&emsp;\u5982\u4e0a\u56fe\u6240\u793a\uff0c\u5047\u8bbe\u73b0\u6709\u4e00\u90e8\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\uff0ck\u8fd1\u90bb\u7684\u601d\u60f3\u662f\u8ba1\u7b97\u51fa\u6570\u636e\u96c6\u4e2d\u6bcf\u4e00\u90e8\u7535\u5f71\u5230\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u7684\u8ddd\u79bb\uff0c\u4e4b\u540e\u627e\u5230$k$\u4e2a\u8fd1\u90bb\u5bf9\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u5206\u7c7b\u3002\u4f46\u662f\u53ef\u4ee5\u53d1\u73b0\u5982\u7535\u5f71C\u8fd9\u6837\u504f\u50fb\u4f4d\u7f6e\u7684\u7535\u5f71\u660e\u663e\u662f\u53ef\u4ee5\u4e0d\u7528\u8ba1\u7b97\u5b83\u4eec\u4e0e\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u7684\u8ddd\u79bb\u7684\u3002<\/p>\n<p>&emsp;&emsp;\u90a3\u73b0\u5728\u5047\u8bbe\u6709\u6ca1\u6709\u8fd9\u4e48\u4e00\u79cd\u53ef\u80fd\uff1f\u6211\u4eec\u4e0d\u518d\u8ba1\u7b97\u6bcf\u90e8\u7535\u5f71\u5230\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u7684\u8ddd\u79bb\uff0c\u800c\u662f\u76f4\u63a5\u5f97\u5230\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u6700\u8fd1\u7684$k$\u90e8\u7535\u5f71\uff1f\u9996\u5148\u8fd9\u79cd\u5047\u8bbe\u5e94\u8be5\u4e0d\u53ef\u80fd\uff0c\u5176\u6b21\u771f\u7684\u6709\uff0c\u90a3\u8fd8\u8981\u5176\u4ed6\u673a\u5668\u5b66\u4e60\u7b97\u6cd5\u4f5c\u751a\uff1f\u90a3\u4e48\u518d\u60f3\u60f3\u80fd\u4e0d\u80fd\u901a\u8fc7\u67d0\u79cd\u65b9\u6cd5\u627e\u5230\u79bb\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u8f83\u8fd1\u7684\u7535\u5f71\u5462\uff1f\u6211\u4eec\u5047\u8bbe\u6709\u8fd9\u79cd\u65b9\u6cd5\uff0c\u5e76\u4e14\u8fd9\u79cd\u65b9\u6cd5\u88ab\u79f0\u4f5ckd\u6811\uff0c\u6211\u4eec\u770b\u770b\u5b83\u662f\u5982\u4f55\u5b9e\u73b0\u7684\u3002<\/p>\n<ol>\n<li>\u6bd4\u5982kd\u6811\u627e\u5230\u7535\u5f71A\u5373\u79bb\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u8f83\u8fd1\u7684\u67d0\u90e8\u7535\u5f71\uff0c\u7136\u540e\u628a\u8ddd\u79bb\u5927\u4e8e\u7535\u5f71A\u5230\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u4e4b\u95f4\u7684\u7535\u5f71\u6392\u9664\u6389\uff0c\u6216\u8005\u662f\u7ee7\u7eed\u627e\u627e\u770b\u6709\u6ca1\u6709\u54ea\u90e8\u7535\u5f71\u5230\u300a\u672a\u77e5\u7c7b\u578b\u7684\u7535\u5f71\u300b\u7684\u8ddd\u79bb\u66f4\u8fd1\uff1f<\/li>\n<li>\u5982\u679c\u53ef\u4ee5\u627e\u5230\u7535\u5f71A\uff0c\u5219\u4e5f\u53ef\u4ee5kd\u6811\u627e\u5230\u7535\u5f71B<\/li>\n<li>\u9012\u5f52\u4f7f\u7528kd\u6811\u641c\u7d22\u76f4\u5230\u627e\u5230\u6700\u8fd1\u7684\u67d0\u51e0\u90e8\u7535\u5f71\uff0c\u505c\u6b62\u641c\u7d22<\/li>\n<\/ol>\n<p>&emsp;&emsp;\u4e0a\u8ff0\u6574\u4e2a\u8fc7\u7a0b\u5176\u5b9e\u5c31\u662fkd\u6811\u5b9e\u73b0\u7684\u4e00\u4e2a\u8fc7\u7a0b\uff0c\u63a5\u4e0b\u6765\u5c06\u4ece\u7406\u8bba\u5c42\u9762\u62bd\u8c61\u7684\u8bb2\u89e3kd\u6811\u3002<\/p>\n<h1>kd\u6811\u8be6\u89e3<\/h1>\n<h2>\u6784\u9020kd\u6811<\/h2>\n<p>&emsp;&emsp;kd\u6811\u4e3b\u8981\u662f\u4e0d\u65ad\u5730\u5212\u5206$k$\u7ef4\u7a7a\u95f4\u3002<\/p>\n<p>&emsp;&emsp;\u5728\u4e00\u4e2a\u4e8c\u7ef4\u7a7a\u95f4\u5e73\u9762\u4e2d\uff0ckd\u6811\u5219\u662f\u4e0d\u65ad\u5730\u4f7f\u7528\u5782\u76f4\u4e8e$x$\u8f74\u6216$y$\u8f74\u7684\u76f4\u7ebf\u628a\u5e73\u9762\u5212\u5206\u6210\u4e00\u7cfb\u5217\u8f83\u5c0f\u7684\u77e9\u5f62\u3002\u5728$k$\u7ef4\u7a7a\u95f4\u4e2d\uff0ckd\u6811\u5219\u662f\u4e0d\u65ad\u5730\u7528\u5782\u76f4\u4e8e\u5750\u6807\u8f74\u7684\u8d85\u5e73\u9762\u5c06$k$\u7ef4\u7a7a\u95f4\u5207\u5206\u6210\u4e00\u7cfb\u5217\u7684$k$\u7ef4\u8d85\u77e9\u5f62\u533a\u57df\u3002<\/p>\n<p>&emsp;&emsp;\u5047\u8bbe\u6709$m$\u4e2a\u5b9e\u4f8b$n$\u7ef4\u7279\u5f81\u7684\u6570\u636e\u96c6<br \/>\n$$<br \/>\nT={(x_1,y_1),(x_2,y_2),\\cdots,(x_m,y_m)}<br \/>\n$$<br \/>\n\u5176\u4e2d$x_i$\u662f\u5b9e\u4f8b\u7684\u7279\u5f81\u5411\u91cf\u5373$({x_i}^{(1)},{x_i}^{(2)},\\cdots,{x_i}^{(n)})$\uff0c$y_i$\u662f\u5b9e\u4f8b\u7684\u7c7b\u522b\uff0c\u6570\u636e\u96c6\u6709${c_1,c_2,\\cdots,c_j}$\u5171$j$\u4e2a\u7c7b\u522b\u3002<\/p>\n<ol>\n<li>\u6784\u9020k\u7ef4\u7a7a\u95f4\u7684\u8d85\u77e9\u5f62\u533a\u57df\u3002\u5982\u679c\u662f\u6709\u4e24\u4e2a\u7279\u5f81$x_1$\u548c$x<em>2$\u7684\u4e8c\u7ef4\u7a7a\u95f4\uff0c\u5219\u662f\u7531$(x1<\/em>{min},x1<em>{max},x2<\/em>{min},x2_{max})$\u6784\u6210\u7684\u77e9\u5f62\u533a\u57df<\/li>\n<li>\u9009\u62e9\u7279\u5f81$x^{(1)}$\u4e3a\u5750\u6807\u8f74\uff0c\u4ee5$T$\u4e2d\u6240\u6709\u5b9e\u4f8b\u7684$x^{(1)}$\u5750\u6807\u7684\u4e2d\u4f4d\u6570\u4f5c\u4e3a\u5207\u5206\u70b9\uff0c\u5c06\u6839\u7ed3\u70b9\u5bf9\u5e94\u7684\u8d85\u77e9\u5f62\u533a\u57df\u5207\u5206\u6210\u5de6\u53f3\u4e24\u4e2a\u5b50\u533a\u57df\u3002\u5c06$x^{(1)}$\u5bf9\u5e94\u503c\u5c0f\u4e8e\u5207\u5206\u70b9\u7684\u5b9e\u4f8b\u5212\u5165\u5de6\u5b50\u533a\u57df\uff1b\u5c06$x^{(1)}$\u5bf9\u5e94\u503c\u5927\u4e8e\u5207\u5206\u70b9\u7684\u5b9e\u4f8b\u5212\u5165\u53f3\u5b50\u533a\u57df\uff1b\u5c06\u5207\u5206\u70b9\u4fdd\u7559\u5728\u6839\u7ed3\u70b9<\/li>\n<li>\u91cd\u590d2\u6b65\u9aa4\uff0c\u5373\u9009\u62e9$x^{(l)}, \\quad (l=1,2,\\cdots,n)$\u4e3a\u5207\u5206\u7684\u5750\u6807\u8f74\uff0c\u4ee5\u8be5\u7ed3\u70b9\u4e2d\u8fd8\u5269\u4e0b\u7684$k$\u4e2a\u5b9e\u4f8b\u7684$x^{(l)}$\u5750\u6807\u7684\u4e2d\u4f4d\u6570\u4f5c\u4e3a\u5207\u5206\u70b9\uff0c\u5c06\u8be5\u7ed3\u70b9\u5bf9\u5e94\u7684\u8d85\u77e9\u5f62\u533a\u57df\u5207\u5206\u6210\u5de6\u53f3\u4e24\u4e2a\u5b50\u533a\u57df\u3002\u5c06$x^{(l)}$\u5bf9\u5e94\u503c\u5c0f\u4e8e\u5207\u5206\u70b9\u7684\u5b9e\u4f8b\u5212\u5165\u5de6\u5b50\u533a\u57df\uff1b\u5c06$x^{(l)}$\u5bf9\u5e94\u503c\u5927\u4e8e\u5207\u5206\u70b9\u7684\u5b9e\u4f8b\u5212\u5165\u53f3\u5b50\u533a\u57df\uff1b\u5c06\u5207\u5206\u70b9\u4fdd\u7559\u5728\u8be5\u7ed3\u70b9<\/li>\n<li>\u5207\u5272\u540e\u7684\u5b50\u533a\u57df\u6ca1\u6709\u5b9e\u4f8b\u65f6\uff0c\u5373\u65e0\u6cd5\u5212\u5206\u65f6\u7ed3\u675f<\/li>\n<\/ol>\n<p>&emsp;&emsp;\u6784\u9020kd\u6811\u65f6\u9700\u8981\u6ce8\u610f\u5de6\u5b50\u7ed3\u70b9\u5bf9\u5e94\u5750\u6807$x^{(l)}$\u5c0f\u4e0e\u5207\u5206\u70b9\u7684$x^{(l)}$\u5750\u6807\uff0c\u53f3\u5b50\u7ed3\u70b9\u5bf9\u5e94\u5750\u6807$x^{(l)}$\u5927\u4e8e\u5207\u5206\u70b9\u7684$x^{(l)}$\u5750\u6807\u3002<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2021\/08\/\u6076\u641e\u56fe02-20.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2021\/08\/\u6076\u641e\u56fe02-20.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h3>\u793a\u4f8b<\/h3>\n<p>&emsp;&emsp;\u5047\u8bbe\u6709\u4e00\u4e2a\u4e8c\u7ef4\u7a7a\u95f4$(x_1,x_2)$\u7684\u6570\u636e\u96c6<br \/>\n$$<br \/>\nT = {(2,3)^T,(5,4)^T,(9,6)^T,(4,7)^T,(8,1)^T,(7,2)^T}<br \/>\n$$<br \/>\n&emsp;&emsp;\u9996\u5148$x$\u8f74\u4e0a\u7684\u6570\u636e\u6709$(2\u30014\u30015\u30017\u30018\u30019)$\uff0c\u4e2d\u4f4d\u6570\u4e3a$7$(\u6ce8\uff1a\u5982\u679c\u4ee5$5$\u5212\u5206\u4e5f\u884c\uff0c\u4f46\u662f\u672c\u6587\u90fd\u662f\u4ee5\u8f83\u5927\u7684\u4f5c\u4e3a\u5207\u5206\u70b9\uff0c\u4f46\u662f\u4e0d\u80fd\u4ee5${\\frac{5+7}{2}}$\u5212\u5206\uff0c\u603b\u4e4b\u5212\u5206\u70b9\u7b26\u5408kd\u6811\u7684\u6784\u9020\u8981\u6c42\u5373\u53ef)\uff0c\u5219\u4ee5$x=7$\u5212\u5206\u4e00\u6b21\u77e9\u5f62\u533a\u57df\uff1b\u5de6\u5b50\u533a\u57df$y$\u8f74\u4e0a\u7684\u6570\u636e\u6709$(3\u30014\u30017)$\uff0c\u4e2d\u4f4d\u6570\u4e3a$4$\uff0c\u5219\u4ee5$y=4$\u5212\u5206\u4e00\u6b21\u6570\u636e\uff0c\u63a5\u7740\u4ee5$x$\u8f74\u4e0a\u7684\u6570\u636e\u5212\u5206\uff0c\u800c$x$\u8f74\u6570\u636e\u53ea\u5269\u4e0b$(2,4)$\uff0c\u76f4\u63a5\u4ee5$x=4$\u5212\u5206\u5de6\u5b50\u533a\u57df\u7684\u53f3\u5b50\u533a\u57df\uff0c\u4ee5$x=2$\u5212\u5206\u5de6\u5b50\u533a\u57df\u7684\u5de6\u5b50\u533a\u57df\uff1b\u53f3\u5b50\u533a\u57df$y$\u8f74\u4e0a\u6570\u636e\u6709$(1\u30016)$\uff0c\u7531\u4e8e\u5212\u5206\u70b9\u9700\u8981\u5927\u4e8e\u5de6\u5b50\u7ed3\u70b9\u7684\uff0c\u56e0\u6b64\u53f3\u5b50\u7ed3\u70b9\u4e3a$(9,6)$\uff0c\u5373\u4ee5$y=6$\u5212\u5206\u5de6\u5b50\u533a\u57df\uff0c\u63a5\u7740\u53ea\u5269\u4e0b\u4e00\u4e2a\u70b9$(8,1)$\uff0c\u53c8\u4ee5$x$\u8f74\u5212\u5206\uff0c\u5219\u4ee5$x=8$\u5212\u5206\u3002<\/p>\n<p>&emsp;&emsp;\u901a\u8fc7\u4ee5\u4e0a\u5212\u5206\uff0c\u5373\u53ef\u5f97\u4ee5\u4e0b\u7279\u5f81\u7a7a\u95f4\u5212\u5206\u56fe\u3002<\/p>\n<pre><code class=\"language-python\"># kd\u6811\u7684\u6784\u9020\u793a\u7279\u5f81\u7a7a\u95f4\u5212\u5206\u56fe\u4f8b\nimport matplotlib.pyplot as plt\nfrom matplotlib.font_manager import FontProperties\n%matplotlib inline\nfont = FontProperties(fname=&#039;\/Library\/Fonts\/Heiti.ttc&#039;)\n\nplt.scatter(2, 3, c=&#039;r&#039;, s=30)\nplt.text(2, 3.5, s=&#039;$(2,3)$&#039;, ha=&#039;center&#039;)\nplt.scatter(5, 4, c=&#039;r&#039;, s=30)\nplt.text(5, 4.5, s=&#039;$(5,4)$&#039;, ha=&#039;center&#039;)\nplt.scatter(9, 6, c=&#039;r&#039;, s=30)\nplt.text(9, 6.5, s=&#039;$(9,6)$&#039;, ha=&#039;center&#039;)\nplt.scatter(4, 7, c=&#039;r&#039;, s=30)\nplt.text(4, 7.5, s=&#039;$(4,7)$&#039;, ha=&#039;center&#039;)\nplt.scatter(8, 1, c=&#039;r&#039;, s=30)\nplt.text(8, 1.5, s=&#039;$(8,1)$&#039;, ha=&#039;center&#039;)\nplt.scatter(7, 2, c=&#039;r&#039;, s=30)\nplt.text(7, 2.5, s=&#039;$(7,2)$&#039;, ha=&#039;center&#039;)\n\nplt.hlines(4, 0, 7, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.hlines(6, 7, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\n\nplt.vlines(2, 0, 4, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(4, 4, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(7, 0, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(8, 0, 6, linestyle=&#039;-&#039;, color=&#039;k&#039;)\n\nplt.xlim(0, 10)\nplt.ylim(0, 10)\nplt.title(&#039;kd\u6811\u6784\u9020-\u793a\u4f8b\u56fe\u4f8b1&#039;, fontproperties=font, fontsize=20)\nplt.show()<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_12_0.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_12_0.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<p>&emsp;&emsp;\u540c\u8d85\u77e9\u5f62\u533a\u57df\u5212\u5206\u4e00\u6837\u53ef\u4ee5\u6784\u9020\u5982\u4e0b\u56fe\u6240\u793a\u7684kd\u4e8c\u53c9\u6811<\/p>\n<p>&emsp;&emsp;\u9996\u5148\u4ee5$x$\u8f74\u4f5c\u4e3a\u5212\u5206\u8f74\uff0c$x$\u8f74\u4e0a\u7684\u6570\u636e\u6709$(2\u30014\u30015\u30017\u30018\u30019)$\uff0c\u4e2d\u4f4d\u6570\u4e3a$7$\uff0c\u6839\u7ed3\u70b9\u4e3a$(7,2)$\uff0c\u5de6\u5b50\u7ed3\u70b9$(2,3)\u3001(4,7)\u3001(5,4)$\uff0c\u53f3\u5b50\u7ed3\u70b9$(8,1)\u3001(9,6)$\uff1b\u4e4b\u540e\u4ee5$y$\u8f74\u4f5c\u4e3a\u5212\u5206\u8f74\uff0c\u5de6\u5b50\u7ed3\u70b9$y$\u8f74\u6709\u6570\u636e$(3\u30014\u30017)$\uff0c\u5219\u5de6\u5b50\u7ed3\u70b9\u7684\u4e2d\u4f4d\u6570\u4e3a$4$\uff0c\u5219\u5de6\u5b50\u7ed3\u70b9$(5,4)$\uff0c\u5de6\u5b50\u7ed3\u70b9\u7684\u5de6\u5b59\u5b50\u7ed3\u70b9$(2,3)$\uff0c\u5de6\u5b50\u7ed3\u70b9\u7684\u53f3\u5b59\u5b50\u7ed3\u70b9$(4,7)$\uff1b\u53f3\u5b50\u7ed3\u70b9$y$\u8f74\u6709\u6570\u636e$(1\u30016)$\uff0c\u5219\u6709\u53f3\u5b50\u7ed3\u70b9$(9,6)$\uff0c\u53f3\u5b50\u7ed3\u70b9\u7684\u5de6\u5b59\u5b50\u7ed3\u70b9$(8,1)$\u3002<\/p>\n<pre><code class=\"language-python\"># kd\u6811\u7684\u6784\u9020kd\u4e8c\u53c9\u6811\u5f62\u6210\u56fe\u4f8b\nimport matplotlib.pyplot as plt\nfrom matplotlib.font_manager import FontProperties\n%matplotlib inline\nfont = FontProperties(fname=&#039;\/Library\/Fonts\/Heiti.ttc&#039;)\n\nplt.scatter(20, 15, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(20, 14.5, s=&#039;$(7,2)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\nplt.annotate(s=&#039;&#039;, xytext=(18.5, 13.5), xy=(13.5, 11.5),\n             arrowprops=dict(arrowstyle=&quot;-&quot;, color=&#039;b&#039;))\n\nplt.scatter(12, 10, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(12, 9.5, s=&#039;$(5,4)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\nplt.annotate(s=&#039;&#039;, xytext=(12, 8), xy=(9, 5),\n             arrowprops=dict(arrowstyle=&quot;-&quot;, color=&#039;b&#039;))\n\nplt.scatter(8, 3, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(8, 2.5, s=&#039;$(2,3)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\n\nplt.scatter(16, 3, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(16, 2.5, s=&#039;$(4,7)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\nplt.annotate(s=&#039;&#039;, xytext=(12, 8), xy=(16, 5),\n             arrowprops=dict(arrowstyle=&quot;-&quot;, color=&#039;b&#039;))\n\nplt.scatter(28, 10, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(28, 9.5, s=&#039;$(9,6)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\nplt.annotate(s=&#039;&#039;, xytext=(21.5, 13.5), xy=(26, 11),\n             arrowprops=dict(arrowstyle=&quot;-&quot;, color=&#039;b&#039;))\n\nplt.scatter(24, 3, c=&#039;white&#039;, edgecolor=&#039;k&#039;, s=2000)\nplt.text(24, 2.5, s=&#039;$(8,1)$&#039;, ha=&#039;center&#039;,\n         fontsize=15, color=&#039;k&#039;, fontweight=&#039;bold&#039;)\nplt.annotate(s=&#039;&#039;, xytext=(27, 8), xy=(24.5, 5),\n             arrowprops=dict(arrowstyle=&quot;-&quot;, color=&#039;b&#039;))\n\nplt.hlines(15, 24, 38, linestyle=&#039;--&#039;, color=&#039;r&#039;)\nplt.text(39, 14.5, ha=&#039;center&#039;, color=&#039;r&#039;, s=&#039;X&#039;, fontsize=15)\nplt.hlines(10, 32, 38, linestyle=&#039;--&#039;, color=&#039;b&#039;)\nplt.text(39, 9.5, ha=&#039;center&#039;, color=&#039;b&#039;, s=&#039;Y&#039;, fontsize=15)\nplt.hlines(3, 28, 38, linestyle=&#039;--&#039;, color=&#039;r&#039;)\nplt.text(39, 2.5, ha=&#039;center&#039;, color=&#039;r&#039;, s=&#039;X&#039;, fontsize=15)\n\nplt.xlim(-1, 40)\nplt.ylim(-1, 20)\nplt.title(&#039;kd\u6811\u6784\u9020-\u793a\u4f8b\u56fe\u4f8b2&#039;, fontproperties=font, fontsize=20)\nplt.show()<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_14_0.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_14_0.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h2>kd\u6811\u641c\u7d22<\/h2>\n<p>&emsp;&emsp;\u4ece\u6839\u7ed3\u70b9\u51fa\u53d1\uff0c\u9012\u5f52\u7684\u5411\u4e0b\u8bbf\u95eekd\u6811\uff0c\u5982\u679c\u76ee\u6807\u70b9$x$\u7684$x^{(l)}$\u7ef4\u7684\u5750\u6807\u5c0f\u4e8e\u5207\u5206\u70b9\u7684\u5750\u6807\uff0c\u5219\u79fb\u52a8\u5230\u5de6\u5b50\u7ed3\u70b9\uff0c\u5426\u5219\u79fb\u52a8\u5230\u53f3\u5b50\u7ed3\u70b9\uff0c\u76f4\u5230\u5b50\u7ed3\u70b9\u4e3a\u53f6\u5b50\u7ed3\u70b9\u4e3a\u6b62\uff0c\u5e76\u5047\u8bbe\u8be5\u53f6\u5b50\u7ed3\u70b9\u4e3a\u76ee\u6807\u70b9\u7684\u5f53\u524d\u6700\u8fd1\u70b9\u3002<\/p>\n<p>&emsp;&emsp;\u9012\u5f52\u7684\u4ece\u8be5\u53f6\u5b50\u7ed3\u70b9\u5411\u4e0a\u56de\u9000\uff0c\u5bf9\u6bcf\u4e2a\u7ed3\u70b9\u4e0a\u7684\u5b9e\u4f8b\u90fd\u8fdb\u884c\u5982\u4e0b\u64cd\u4f5c\uff1a<\/p>\n<ol>\n<li>\u5982\u679c\u8be5\u5b9e\u4f8b\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb\u66f4\u8fd1\uff0c\u5219\u4ee5\u8be5\u5b9e\u4f8b\u70b9\u4e3a\u5f53\u524d\u6700\u8fd1\u70b9<\/li>\n<li>\u68c0\u67e5\u5f53\u524d\u6700\u8fd1\u70b9\u7236\u7ed3\u70b9\u7684\u53e6\u4e00\u5b50\u7ed3\u70b9\u5bf9\u5e94\u7684\u533a\u57df\u662f\u5426\u6709\u66f4\u8fd1\u7684\u70b9\uff0c\u5373\u53e6\u4e00\u5b50\u7ed3\u70b9\u7684\u8d85\u77e9\u5f62\u533a\u57df\u662f\u5426\u4e0e\u4ee5\u76ee\u6807\u70b9\u4e3a\u7403\u5fc3\u3001\u4ee5\u76ee\u6807\u70b9\u5230\u5f53\u524d\u6700\u8fd1\u70b9\u7684\u534a\u5f84\u5f62\u6210\u7684\u8d85\u7403\u4f53\u662f\u5426\u76f8\u4ea4\n<ol>\n<li>\u5982\u679c\u76f8\u4ea4\uff0c\u5219\u53e6\u4e00\u5b50\u7ed3\u70b9\u5bf9\u5e94\u7684\u8d85\u77e9\u5f62\u533a\u57df\u5185\u5b58\u5728\u79bb\u76ee\u6807\u70b9\u66f4\u8fd1\u7684\u70b9\uff0c\u79fb\u5230\u53e6\u4e00\u5b50\u7ed3\u70b9\u7ee7\u7eed\u9012\u5f52\u641c\u7d22<\/li>\n<li>\u5982\u679c\u4e0d\u76f8\u4ea4\uff0c\u5219\u5411\u4e0a\u56de\u9000<\/li>\n<\/ol>\n<\/li>\n<li>\u5f53\u56de\u9000\u5230\u6839\u7ed3\u70b9\u65f6\u7ed3\u675f\uff0c\u76ee\u6807\u70b9\u7684\u6700\u8fd1\u90bb\u70b9\u4e3a\u5f53\u524d\u6700\u8fd1\u70b9<\/li>\n<\/ol>\n<p>&emsp;&emsp;\u4e0a\u8ff0kd\u6811\u641c\u7d22\u7684\u8fc7\u7a0b\u53ef\u4ee5\u770b\u51fa\uff0c\u7531\u4e8e\u5f88\u591a\u5b9e\u4f8b\u70b9\u6240\u5728\u7684\u8d85\u77e9\u5f62\u533a\u57df\u548c\u8d85\u7403\u4f53\u4e0d\u76f8\u4ea4\uff0c\u538b\u6839\u4e0d\u9700\u8981\u8ba1\u7b97\u8ddd\u79bb\uff0c\u6253\u6253\u8282\u7701\u4e86\u8ba1\u7b97\u65f6\u95f4\u3002<\/p>\n<p>&emsp;&emsp;\u4f46\u662f\u503c\u5f97\u6ce8\u610f\u7684\u662fkd\u6811\u7684\u5e73\u5747\u8ba1\u7b97\u590d\u6742\u5ea6\u4e3a$O(\\log{N})$\uff0c\u5f53\u7279\u5f81\u7ef4\u6570\u63a5\u8fd1\u8bad\u7ec3\u96c6\u5b9e\u4f8b\u6570\u65f6\uff0ckd\u6811\u7684\u641c\u7d22\u6548\u7387\u5219\u4f1a\u8fc5\u901f\u4e0b\u964d\uff0c\u51e0\u4e4e\u63a5\u8fd1\u7ebf\u6027\u626b\u63cf\u3002<\/p>\n<h3>\u793a\u4f8b<\/h3>\n<p>&emsp;&emsp;\u63a5\u4e0b\u6765\u5c06\u62ff\u4e0a\u4e00\u8282\u6784\u9020\u7684kd\u6811\u4e3e\u4f8bkd\u6811\u641c\u7d22\u7684\u6574\u4e2a\u8fc7\u7a0b\uff0c\u5047\u8bbe\u76ee\u6807\u70b9\u4e3a$(2,4.5)$\u3002<\/p>\n<ol>\n<li>\u641c\u7d22\u76ee\u6807\u70b9\u5bf9\u5e94\u7684\u53f6\u5b50\u7ed3\u70b9\n<ol>\n<li>\u4ece\u6839\u7ed3\u70b9$(7,2)$\u5f00\u59cb\u67e5\u627e\uff0c\u7531\u4e8e$(7,2)$\u662f\u7531$x=7$\u5212\u5206\u7684\uff0c\u5e76\u4e14\u76ee\u6807\u70b9\u7684$x$\u503c\u4e3a$2$\uff0c\u7531\u4e8e$2&lt;7$\u5219\u5230\u5de6\u5b50$(5,4)$\u7ed3\u70b9<\/li>\n<li>\u7531\u4e8e$(5,4)$\u662f\u7531$y=4$\u5206\u9694\u8d85\u5e73\u9762\u7684\uff0c\u5e76\u4e14\u76ee\u6807\u70b9\u7684$y$\u503c\u4e3a$4.5$\uff0c\u7531\u4e8e$4.5&gt;4$\u5219\u5230\u53f3\u5b50$(4,7)$\u53f6\u5b50\u7ed3\u70b9<\/li>\n<li>\u5047\u8bbe$(4,7)$\u53f6\u5b50\u7ed3\u70b9\u4e3a\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9<\/li>\n<li>\u76ee\u6807\u6389\u641c\u7d22\u5230\u53f6\u5b50\u7ed3\u70b9\u7684\u8def\u5f84\u4e3a$(7,2)\\rightarrow(5,4)\\rightarrow(4,7)$<\/li>\n<\/ol>\n<\/li>\n<li>\u641c\u7d22\u76ee\u6807\u70b9\u5bf9\u5e94\u7684\u5f53\u524d\u6700\u8fd1\u70b9\n<ol>\n<li>\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9$(4,7)$\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb\u4e3a$3.2$\uff0c\u800c\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9\u7684\u7236\u8282\u70b9$(5,4)$\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb\u4e3a$3.0$\uff0c\u5219\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9\u66f4\u65b0\u4e3a$(5,4)$<\/li>\n<li>\u4ee5\u4e0b\u56fe\u84dd\u8272\u4e94\u89d2\u661f\u76ee\u6807\u70b9$(2,4.5)$\u4e3a\u5706\u5fc3\uff0c\u4ee5\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9$(5\uff0c4)$\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb$3.0$\u4e3a\u534a\u5f84\u505a\u4e00\u4e2a\u8d85\u7403\u4f53\uff0c\u5373\u4e0b\u56fe\u7684\u7ea2\u8272\u5706\u5708<\/li>\n<li>\u53ef\u4ee5\u53d1\u73b0\u7ea2\u8272\u5706\u5708\u548c$y=4$\u8d85\u5e73\u9762\u76f8\u4ea4\uff0c\u56e0\u6b64\u8fdb\u5165$(5,4)$\u7684\u5de6\u5b50\u7ed3\u70b9\u67e5\u627e\uff0c\u5373\u627e\u5230$(2,3)$<\/li>\n<li>\u8ba1\u7b97$(2,3)$\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb\u4e3a$1.5$\uff0c\u5219\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9\u66f4\u65b0\u4e3a$(2,3)$<\/li>\n<li>\u4ee5\u4e0b\u56fe\u84dd\u8272\u4e94\u89d2\u661f\u76ee\u6807\u70b9$(2,4.5)$\u4e3a\u5706\u5fc3\uff0c\u4ee5\u5f53\u524d\u6700\u8fd1\u7ed3\u70b9$(2\uff0c3)$\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb$1.5$\u4e3a\u534a\u5f84\u505a\u4e00\u4e2a\u8d85\u7403\u4f53\uff0c\u5373\u4e0b\u56fe\u7684\u7eff\u8272\u5706\u5708<\/li>\n<li>\u7531\u4e8e\u7ed3\u70b9$(2,3)$\u4e3a\u53f6\u5b50\u7ed3\u70b9\uff0c\u5f00\u59cb\u6cbf\u7236\u7ed3\u70b9\u56de\u6eaf\uff0c\u7236\u7ed3\u70b9$(5,4)$\u5df2\u7ecf\u8003\u8651\u8fc7\uff0c\u7ee7\u7eed\u5f80\u4e0a\u56de\u6eaf\u5230$(7,2)$<\/li>\n<li>\u7eff\u8272\u5706\u5708\u548c$x=7$\u6ca1\u6709\u76f8\u4ea4\uff0c\u53c8\u7531\u4e8e$(7,2)$\u4e3a\u6839\u8282\u70b9\uff0c\u641c\u7d22\u7ed3\u675f<\/li>\n<li>\u901a\u8fc7\u4e0a\u8ff0\u641c\u7d22\u76ee\u6807\u70b9\u6700\u8fd1\u70b9\u4e3a$(2,3)$\uff0c\u6700\u8fd1\u8ddd\u79bb\u4e3a$1.5$<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p>&emsp;&emsp;\u503c\u5f97\u6ce8\u610f\u7684\u662f\u4e0a\u8ff0\u90fd\u662f\u4ee5\u6700\u8fd1\u90bb\u5c55\u5f00\u8ba8\u8bbakd\u6811\u7684\uff0c\u5982\u679c\u60f3\u5f97\u5230$k$\u4e2a\u8fd1\u90bb\uff0c\u53ea\u9700\u8981\u6700\u540e\u4fdd\u7559$k$\u4e2a\u6700\u8fd1\u90bb\u7684\u7ed3\u70b9\u4e0a\u7684\u5b9e\u4f8b\u70b9\u5373\u53ef\uff0c\u4e4b\u540e\u4f9d\u636e\u591a\u6570\u8868\u51b3\u6cd5\u5373\u53ef\u83b7\u5f97\u76ee\u6807\u70b9\u7684\u7c7b\u522b\uff1b\u5982\u679c\u662f\u56de\u5f52\u95ee\u9898\uff0c\u53d6$k$\u4e2a\u8fd1\u90bb\u70b9\u7684\u6807\u8bb0\u503c\u7684\u5e73\u5747\u6570\u6216\u4e2d\u4f4d\u6570\u5373\u53ef\u3002<\/p>\n<p><!--more--><\/p>\n<pre><code class=\"language-python\"># kd\u6811\u7684\u6784\u9020\u793a\u7279\u5f81\u7a7a\u95f4\u5212\u5206\u56fe\u4f8b\nimport matplotlib.pyplot as plt\nfrom matplotlib.font_manager import FontProperties\n%matplotlib inline\nfont = FontProperties(fname=&#039;\/Library\/Fonts\/Heiti.ttc&#039;)\n\nplt.scatter(2, 3, c=&#039;r&#039;, s=30)\nplt.text(2, 3.5, s=&#039;$(2,3)$&#039;, ha=&#039;center&#039;)\nplt.scatter(5, 4, c=&#039;r&#039;, s=30)\nplt.text(5, 4.5, s=&#039;$(5,4)$&#039;, ha=&#039;center&#039;)\nplt.scatter(9, 6, c=&#039;r&#039;, s=30)\nplt.text(9, 6.5, s=&#039;$(9,6)$&#039;, ha=&#039;center&#039;)\nplt.scatter(4, 7, c=&#039;r&#039;, s=30)\nplt.text(4, 7.5, s=&#039;$(4,7)$&#039;, ha=&#039;center&#039;)\nplt.scatter(8, 1, c=&#039;r&#039;, s=30)\nplt.text(8, 1.5, s=&#039;$(8,1)$&#039;, ha=&#039;center&#039;)\nplt.scatter(7, 2, c=&#039;r&#039;, s=30)\nplt.text(7, 2.5, s=&#039;$(7,2)$&#039;, ha=&#039;center&#039;)\n\nplt.hlines(4, 0, 7, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.hlines(6, 7, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\n\nplt.vlines(2, 0, 4, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(4, 4, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(7, 0, 10, linestyle=&#039;-&#039;, color=&#039;k&#039;)\nplt.vlines(8, 0, 6, linestyle=&#039;-&#039;, color=&#039;k&#039;)\n\nplt.scatter(2, 4.5, s=30410, c=&#039;white&#039;, edgecolor=&#039;r&#039;)\nplt.scatter(2, 4.5, s=15000, c=&#039;white&#039;, edgecolor=&#039;g&#039;)\nplt.scatter(2, 4.5, s=50, c=&#039;b&#039;, marker=&#039;*&#039;)\nplt.text(2, 5, s=&#039;\u76ee\u6807\u70b9$(2,4.5)$&#039;, ha=&#039;center&#039;,fontproperties=font)\nplt.scatter(2, 3, c=&#039;r&#039;, s=30)\nplt.scatter(4, 7, c=&#039;r&#039;, s=30)\n\nplt.xlim(0, 10)\nplt.ylim(0, 10)\nplt.title(&#039;kd\u6811\u641c\u7d22-\u793a\u4f8b\u56fe\u4f8b&#039;, fontproperties=font, fontsize=20)\nplt.show()<\/code><\/pre>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_19_0.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2022\/02\/02-17-kd\u6811_19_0.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" \/><\/div><\/p>\n<h1>kd\u6811\u6d41\u7a0b<\/h1>\n<h2>\u8f93\u5165<\/h2>\n<p>&emsp;&emsp;\u6709$m$\u4e2a\u5b9e\u4f8b$n$\u7ef4\u7279\u5f81\u7684\u6570\u636e\u96c6<br \/>\n$$<br \/>\nT={(x_1,y_1),(x_2,y_2),\\cdots,(x_m,y_m)}<br \/>\n$$<br \/>\n\u5176\u4e2d$x_i$\u662f\u5b9e\u4f8b\u7684\u7279\u5f81\u5411\u91cf\u5373$({x_i}^{(1)},{x_i}^{(2)},\\cdots,{x_i}^{(n)})$\u3002<\/p>\n<h2>\u8f93\u51fa<\/h2>\n<p>&emsp;&emsp;\u8ddd\u79bb\u76ee\u6807\u70b9\u6700\u8fd1\u7684$k$\u4e2a\u5b9e\u4f8b\u53ca$k$\u4e2a\u5b9e\u4f8b\u5230\u76ee\u6807\u70b9\u7684\u8ddd\u79bb\u3002<\/p>\n<h2>\u6d41\u7a0b<\/h2>\n<ol>\n<li>\u6784\u9020kd\u6811<\/li>\n<li>\u641c\u7d22\u79bb\u76ee\u6807\u70b9\u6700\u8fd1\u7684$k$\u4e2a\u5b9e\u4f8b\u70b9<\/li>\n<li>\u5206\u7c7b\u95ee\u9898\u4f9d\u636e\u591a\u6570\u8868\u51b3\u6cd5\u5373\u53ef\u83b7\u5f97\u76ee\u6807\u70b9\u7684\u7c7b\u522b\uff1b\u5982\u679c\u662f\u56de\u5f52\u95ee\u9898\uff0c\u53d6 ? 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