{"id":806,"date":"2019-01-10T20:14:48","date_gmt":"2019-01-10T12:14:48","guid":{"rendered":"https:\/\/mnihyc.tk\/blog\/?p=806"},"modified":"2020-02-09T03:08:49","modified_gmt":"2020-02-08T19:08:49","slug":"yzoj-p3669-usaco2008-mar%e5%9c%9f%e5%9c%b0%e8%b4%ad%e4%b9%b0","status":"publish","type":"post","link":"https:\/\/0self.mnihyc.com\/blog\/archives\/806","title":{"rendered":"YZOJ P3669 [USACO2008 Mar]\u571f\u5730\u8d2d\u4e70"},"content":{"rendered":"<h1 style=\"text-align: center;\">YZOJ P3669 [USACO2008 Mar]\u571f\u5730\u8d2d\u4e70<\/h1>\n<p style=\"text-align: center;\">\u65f6\u95f4\u9650\u5236\uff1a1000MS \u5185\u5b58\u9650\u5236\uff1a262144KB<\/p>\n<p style=\"text-align: center;\">\u96be\u5ea6\uff1a<span style=\"color: #ff6600;\">\\(6.0\\)<\/span> \uff08\u81ea\u8bc4\uff09<\/p>\n<ul>\n<li>\n<h3><strong>\u9898\u76ee\u63cf\u8ff0<\/strong><\/h3>\n<\/li>\n<\/ul>\n<p>\u519c\u592b John \u51c6\u5907\u6269\u5927\u4ed6\u7684\u519c\u573a\uff0c\u4ed6\u6b63\u5728\u8003\u8651 \\(N\\) \uff08\\(1 \\leq N \\leq 1,000,000\\)\uff09 \u5757\u957f\u65b9\u5f62\u7684\u571f\u5730\u3002<\/p>\n<p>\u6bcf\u5757\u571f\u5730\u7684\u957f\u5bbd\u6ee1\u8db3 (\\(1 \\leq\\) \u5bbd \\(\\leq 1,000,000\\)\uff0c \\(1 \\leq\\) \u957f \\(\\leq 1,000,000\\)\uff09\u3002\u6bcf\u5757\u571f\u5730\u7684\u4ef7\u683c\u662f\u5b83\u7684\u9762\u79ef\uff0c\u4f46 FJ \u53ef\u4ee5\u540c\u65f6\u8d2d\u4e70\u591a\u5757\u571f\u5730\u3002<\/p>\n<p>\u8fd9\u4e9b\u571f\u5730\u7684\u4ef7\u683c\u662f\u5b83\u4eec\u6700\u5927\u7684\u957f\u4e58\u4ee5\u5b83\u4eec\u6700\u5927\u7684\u5bbd\uff0c\u4f46\u662f\u571f\u5730\u7684\u957f\u5bbd\u4e0d\u80fd\u4ea4\u6362\u3002\u5982\u679c FJ \u4e70\u4e00\u5757 \\(3 \\times 5\\) \u7684\u5730\u548c\u4e00\u5757 \\(5 \\times 3\\) \u7684\u5730\uff0c\u5219\u4ed6\u9700\u8981\u4ed8 \\(5 \\times 5=25\\)\u3002<\/p>\n<p>FJ \u5e0c\u671b\u4e70\u4e0b\u6240\u6709\u7684\u571f\u5730\uff0c\u4f46\u662f\u4ed6\u53d1\u73b0\u5206\u7ec4\u6765\u4e70\u8fd9\u4e9b\u571f\u5730\u53ef\u4ee5\u8282\u7701\u7ecf\u8d39\u3002\u4ed6\u9700\u8981\u4f60\u5e2e\u52a9\u4ed6\u6c42\u51fa\u6700\u5c0f\u7684\u7ecf\u8d39\u3002<\/p>\n<ul>\n<li>\n<h3><strong>\u8f93\u5165\u683c\u5f0f<\/strong><\/h3>\n<\/li>\n<\/ul>\n<p>\u8f93\u5165\u6587\u4ef6\u7684\u7b2c \\(1\\) \u884c\u4e00\u4e2a\u6570 \\(N\\)\uff0c \u8868\u793a\u571f\u5730\u5757\u6570\u3002\u7b2c \\(2\\) \u884c\u81f3\u7b2c \\(N+1\\) \u884c\uff0c\u6bcf\u884c\u5305\u542b\u4e24\u4e2a\u6570\uff0c\u8868\u793a\u7b2c \\(i\\) \u5757\u571f\u5730\u7684\u957f\u548c\u5bbd\u3002<\/p>\n<ul>\n<li>\n<h3><strong>\u8f93\u51fa\u683c\u5f0f<\/strong><\/h3>\n<\/li>\n<\/ul>\n<p>\u6700\u5c0f\u7684\u53ef\u884c\u8d39\u7528\u3002<\/p>\n<ul>\n<li>\n<h3><strong>\u6837\u4f8b\u8f93\u5165<\/strong><\/h3>\n<\/li>\n<\/ul>\n<pre class=\"\">4\r\n100 1\r\n15 15\r\n20 5\r\n1 100<\/pre>\n<ul>\n<li>\n<h3><strong>\u6837\u4f8b\u8f93\u51fa<\/strong><\/h3>\n<\/li>\n<\/ul>\n<pre class=\"\">500<\/pre>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><!--more--><\/p>\n<hr \/>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>wtcl \\(O(N^2)\\) \u7684 DP \u90fd\u60f3\u4e0d\u51fa\u6765\u7136\u540e\u6210\u529f\u7206\u4e86\u96f6\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>\u6ce8\u610f\u5230\u571f\u5730\u7684\u9009\u62e9\u662f\u5206\u7ec4\u7684\uff0c\u7ec4\u6570\u6ca1\u6709\u9650\u5236\uff0c\u6bcf\u4e00\u7ec4\u53ef\u4ee5\u5305\u62ec\u7684\u77e9\u5f62\u4e5f\u6ca1\u6709\u7279\u6b8a\u7684\u9650\u5236\uff0c\u8fd9\u6837\u8303\u56f4\u592a\u5927\u4e86\uff0c\u65e0\u6cd5\u8fdb\u884c\u5904\u7406\u3002\u600e\u4e48\u529e\u5462\uff1f\uff1f\uff1f<\/p>\n<p>\u9996\u5148\u6ce8\u610f\u5230\u7684\u662f\uff0c\u5982\u679c\u6709\u51fa\u73b0\u67d0\u4e2a\u77e9\u5f62<strong>\u5b8c\u5168\u5305\u542b<\/strong>\u53e6\u4e00\u77e9\u5f62\u7684\u60c5\u51b5\uff0c\u90a3\u4e48\u90a3\u4e2a\u5c0f\u77e9\u5f62\u5c31\u53ef\u4ee5\u76f4\u63a5\u6254\u6389\u4e86\u3002\u56e0\u4e3a\u5728\u9009\u5927\u77e9\u5f62\u7684\u540c\u65f6\u9009\u5c0f\u77e9\u5f62\uff0c\u90a3\u4e48\u4ee3\u4ef7\u4e0d\u4f1a\u53d8\u5c0f\uff1b\u5982\u679c\u9009\u62e9\u5c0f\u7684\u77e9\u5f62\uff0c\u90a3\u4e48\u4e00\u5b9a\u8981\u9009\u5927\u7684\u77e9\u5f62\uff0c\u5426\u5219\u80af\u5b9a\u662f\u4e0d\u4f18\u7684\u3002<\/p>\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u5c31\u662f\u5bf9\u4e8e\u4e24\u4e2a\u77e9\u5f62 \\(A, B\\) \uff0c\u82e5 \\(\\left(length_A \\geq length_B\\right) \\land \\left(width_A \\geq width_B\\right)\\) \uff0c\u90a3\u4e48\u77e9\u5f62 \\(B\\) \u5c31\u53ef\u4ee5\u76f4\u63a5\u88ab\u5220\u53bb\uff0c\u4e0d\u9700\u8981\u8fdb\u884c\u5904\u7406\u3002<\/p>\n<p>\u5904\u7406\u7684\u65f6\u5019\u53ef\u4ee5\u5148\u4ee5\u77e9\u5f62\u7684<strong>\u957f\u4e3a\u7b2c\u4e00\u5173\u952e\u5b57<\/strong>\uff0c\u77e9\u5f62\u7684<strong>\u5bbd\u4e3a\u7b2c\u4e8c\u5173\u952e\u5b57<\/strong>\u8fdb\u884c\u5347\u5e8f\u6392\u5e8f\u3002\u56e0\u4e3a\u8fd9\u6837\u968f\u7740 \\(i\\) \u7684\u589e\u5927\uff0c\u77e9\u5f62\u7684\u957f\u90fd\u662f\u975e\u4e25\u683c\u5355\u8c03\u9012\u589e\u7684\uff0c\u6ee1\u8db3\u4e86 \\(length_A \\geq length_B\\) \uff0c\u6240\u4ee5\u63a5\u4e0b\u6765\u53ea\u8981\u6ee1\u8db3 \\(width_A \\geq width_B\\)\u5c31\u53ef\u4ee5\u4e86\u3002\uff08\u6ce8\u610f\u539f\u5e8f\u5217 \\(orect\\) \u548c\u65b0\u5e8f\u5217 \\(rect\\) \u4e0d\u8981\u641e\u6df7\u4e86\uff09<\/p>\n<pre class=\"lang:default decode:true\">std::sort(&amp;orect[1],&amp;orect[N+1]);\r\nregister int nN=0;\r\nfor(register int i=1;i&lt;=N;i++)\r\n{\r\n\twhile(nN &amp;&amp; rect[nN].w&lt;orect[i].w)\r\n\t\tnN--;\r\n\trect[++nN]=orect[i];\r\n}\r\nN=nN;<\/pre>\n<p>\u8fd9\u6837\u5c31\u53ef\u4ee5\u5f97\u5230<strong>\u957f\u975e\u4e25\u683c\u5355\u589e<\/strong>\uff0c<strong>\u5bbd\u975e\u4e25\u683c\u5355\u51cf<\/strong>\u7684\u77e9\u5f62\u5e8f\u5217\uff08\u6ce8\u610f\u56e0\u4e3a\u5220\u53bb\u4e86\u9012\u589e\u7684\u5bbd\uff0c\u6240\u4ee5\u5bbd\u662f<strong>\u975e\u4e25\u683c\u5355\u51cf<\/strong>\u7684\uff09\u3002<\/p>\n<p>\u6709\u4e86\u8fd9\u4e2a\u6027\u8d28\uff0c\u5c31\u53ef\u4ee5\u63a8\u5bfc\u51faDP\u65b9\u7a0b\u4e86\u3002\u56e0\u4e3a\u957f\u3001\u5bbd\u90fd\u662f\u5355\u8c03\u7684\uff0c\u6240\u4ee5\u663e\u7136\u9009\u62e9<strong>\u8fde\u7eed\u7684\u4e00\u4e9b\u77e9\u5f62<\/strong>\u4f5c\u4e3a\u4e00\u7ec4\u8d2d\u4e70\u662f\u6700\u4f18\u7684\u3002<\/p>\n<p>\u6240\u4ee5\u8bbe \\(f_i\\) \u4e3a\u8d2d\u4e70\u5230\u7b2c \\(i\\) \u4e2a\u77e9\u5f62\u65f6\uff0c\u6240\u8017\u6700\u5c0f\u7684\u8d39\u7528\u3002\u8f6c\u79fb \\(f_i=\\min\\limits_{0 \\leq j &lt; i}\\{f_j+cost_{j+1, i}\\}\\) \u3002\u7531\u4e8e\u957f\u3001\u5bbd\u5355\u8c03\uff0c\u6240\u4ee5 \\(cost_{j+1, i}=width_{j+1} \\cdot length_{i}\\) \u3002<\/p>\n<p>\u72b6\u6001\u6570 \\(O(N)\\) \uff0c\u8f6c\u79fb\u8d39\u7528 \\(O(N)\\) \uff0c\u6240\u4ee5\u65f6\u95f4\u590d\u6742\u5ea6\u4e3a \\(O(N^2)\\) \u65e0\u6cd5\u901a\u8fc7\u672c\u9898\u3002<\/p>\n<p>\u5982\u679c\u662f\u7a0d\u6709\u77e5\u8bc6\u50a8\u5907\u7684\u4eba\uff08\u53ef\u60dc\u6211\u4e0d\u662f\uff09\u5c31\u4f1a\u7acb\u523b\u53d1\u73b0 \u8fd9\u4e2a\u662f\u4e2a\u7ecf\u5178\u7684 1D1D \u7684 DP\u659c\u7387\u4f18\u5316\u6a21\u578b\u3002<\/p>\n<p>\u5bf9\u4e8e\u659c\u7387\u4f18\u5316\uff0corzCJKimmortalCO \u63ed\u793a\u4e86\u4e00\u79cd\u65b0\u7684\u65b9\u6cd5\u6765\u7406\u89e3\u5b83\uff0c\u6211\u4f1a\u5728\u4e0b\u9762\u8fdb\u884c\u8be6\u7ec6\u8bf4\u660e\u3002<\/p>\n<p>\u8fd9\u662f\u521a\u624d\u63a8\u5bfc\u7684\u8f6c\u79fb\u65b9\u7a0b\uff1a \\(f_i=\\min\\limits_{0 \\leq j &lt; i}\\{f_j+w_{j+1} \\cdot l_{i}\\}\\) \uff0c\u73b0\u5728\u6211\u4eec\u8981\u8d4b\u4e88\u5b83\u4ee5<strong>\u51e0\u4f55\u610f\u4e49<\/strong>\u3002\uff08\u65f6\u523b\u6ce8\u610f\uff0c\u8fd9\u4e2a\u65b9\u7a0b\u7684\u610f\u4e49\u662f\u5bf9\u4e8e\u4e00\u4e2a \\(i\\) \u5728 \\(0 \\leq j &lt; i\\) \u8303\u56f4\u5185\u5bfb\u627e\u6700\u5c0f\u7684 \\(f_j+w_{j+1} \\cdot l_{i}\\)\uff09<\/p>\n<p>\u8bbe \\(x_j=-w_{j+1}, y_j=f_j\\) \uff0c\u90a3\u4e48\u9700\u8981\u6700\u5c0f\u5316\u7684\u5f0f\u5b50\u5c31\u53d8\u4e3a\u4e86 \\(y_j-x_j \\cdot l_i\\) \u3002\u540c\u65f6\u8fd8\u6ce8\u610f\u5230\u76f4\u7ebf\u7684\u89e3\u6790\u5f0f\u4e3a \\(y=kx+b\\) \uff0c\u90a3\u4e48\u622a\u8ddd \\(b=y-kx\\) \uff0c\u6240\u4ee5\u8fd9\u4e2a\u9700\u8981\u6700\u5c0f\u5316\u7684\u5f0f\u5b50\u5176\u5b9e\u8868\u793a\u7684\u662f\u4e00\u6761<strong>\u659c\u7387\u4e3a \\(l_i\\) \u7684\u76f4\u7ebf\u7684\u622a\u8ddd<\/strong>\uff01<\/p>\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u628a\u6240\u6709\u53ef\u4ee5\u8fdb\u884c\u8f6c\u79fb\u7684 \\(j\\) \u90fd\u8868\u793a\u4e3a\u4e8c\u7ef4\u5e73\u9762\u4e0a\u7684<strong>\u4e00\u4e2a\u70b9 \\(p_j=\\left(x_j, y_j\\right)\\)<\/strong> \uff0c\u6211\u4eec\u9700\u8981\u505a\u7684\u5c31\u662f\u5728\u6240\u6709\u8fd9\u6837\u7684\u70b9\u4e2d\uff0c\u627e\u5230\u4e00\u4e2a\u70b9\uff0c<strong>\u4f7f<span style=\"text-decoration: underline;\">\u7ecf\u8fc7\u5b83<\/span>\u7684\u659c\u7387\u4e3a \\(l_i\\) \u7684\u76f4\u7ebf\u7684<span style=\"text-decoration: underline;\">\u622a\u8ddd\u6700\u5c0f<\/span><\/strong>\uff01<\/p>\n<p>\u597d\u7684\uff0c\u73b0\u5728\u60f3\u8c61\u4e00\u6761<strong>\u659c\u7387\u56fa\u5b9a<\/strong>\u7684\u76f4\u7ebf\u4ece\u4e0b\u5f80\u4e0a\u5e73\u79fb\uff0c\u5f53\u5b83\u7b2c\u4e00\u6b21\u7ecf\u8fc7\u67d0\u4e2a\u70b9 \\(p_j\\) \u65f6\uff0c\u8fd9\u65f6\u7684\u622a\u8ddd\u80af\u5b9a\u53d6\u5230\u6700\u5c0f\u503c\u3002\u90a3\u4e48\u8fd9\u4e2a\u70b9 \\(p_j\\) \u5728\u4ec0\u4e48\u5730\u65b9\u5462\uff1f\u663e\u7136\uff0c\u5b83\u4f1a\u5728<span style=\"text-decoration: underline;\"><strong>\u4e0b\u51f8\u58f3<\/strong><\/span>\u4e0a\u3002\u8bbe\u6b64\u65f6\u8fd9\u6761\u76f4\u7ebf\u7684\u659c\u7387\u4e3a \\(k\\) \uff0c\\(p_j\\) \u5230\u51f8\u58f3\u7684\u4e0a\u4e00\u4e2a\u70b9\u7684\u76f4\u7ebf\u7684\u659c\u7387\u4e3a \\(k_1\\) \uff0c\\(p_j\\) \u5230\u51f8\u58f3\u7684\u4e0b\u4e00\u4e2a\u70b9\u7684\u76f4\u7ebf\u7684\u659c\u7387\u4e3a \\(k_2\\) \uff0c\u90a3\u4e48 \\(k \\in [k_1, k_2]\\) \u3002\u7531\u4e8e\u4e0b\u51f8\u58f3\u4e0a<strong>\u659c\u7387\u5355\u8c03\u9012\u589e<\/strong>\uff0c\u6240\u4ee5\u5728\u5355\u8c03\u6808\u4e0a<strong>\u4e8c\u5206<\/strong>\u51b3\u7b56\u70b9\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n<p>\u4f46\u662f\u7531\u4e8e\u8fd9\u9898 \\(l_i\\) \u662f\u5355\u589e\u7684\uff0c\u4e5f\u5c31\u610f\u5473\u7740\u659c\u7387\u90fd\u662f\u5355\u589e\u7684\uff0c\u7a0d\u52a0\u5904\u7406\u540e\u76f4\u63a5\u53d6\u961f\u5934\u5143\u7d20\u5373\u53ef\uff0c\u4e0d\u9700\u8981\u4e8c\u5206\u3002<\/p>\n<p>\u9700\u8981\u7a0d\u52a0\u6ce8\u610f\u7684\u662f\uff0c\u8fd9\u91cc\u7684 \\(x_j\\) \u4e5f\u662f\u5355\u589e\u7684\uff0c\u5426\u5219\u5c31\u9700\u8981 CDQ\u5206\u6cbb \u6216\u8005 Splay \u6765\u7ef4\u62a4\u3002<\/p>\n<p>\u8bf4\u5b9e\u8bdd\uff0c\u6211\u89c9\u5f97\u4e0a\u9762\u7684\u89e3\u91ca\u5b9e\u5728\u662f\u592a\u597d\u4e86\uff0c\u503c\u5f97\u591a\u591a\u601d\u8003\u548c\u4f53\u4f1a\u3002<\/p>\n<p>\u56de\u5230\u672c\u9898\uff0c\u5269\u4e0b\u7684\u5de5\u4f5c\u53ea\u662f\u7ef4\u62a4\u4e0b\u51f8\u58f3\u800c\u5df2\u3002<\/p>\n<p>\u5982\u679c\u961f\u5934\u7684<strong>\u524d\u4e24\u4e2a\u70b9\u7684\u76f4\u7ebf\u7684\u659c\u7387<\/strong> \u6bd4 \u5f53\u524d\u7684\u659c\u7387 \\(l_i\\) \u8fd8<strong>\u5c0f<\/strong>\uff0c\u90a3\u4e48\u961f\u5934\u7684\u90a3\u4e2a\u70b9\u80af\u5b9a\u662f\u53d6\u4e0d\u5230\u4e86\uff0c\u56e0\u4e3a\u8fd9\u6761\u76f4\u7ebf\u4f1a\u5728\u5230\u8fbe\u7b2c\u4e00\u4e2a\u70b9\u4e4b\u524d<strong>\u5148\u5230\u8fbe\u7b2c\u4e8c\u4e2a\u70b9<\/strong>\uff0c\u6240\u4ee5\u5f39\u51fa\u961f\u5934\u5143\u7d20\u76f4\u5230\u6ee1\u8db3\u6761\u4ef6\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u653e\u5fc3\u7684\u53d6\u961f\u5934\u5143\u7d20\u4f5c\u4e3a\u6700\u5c0f\u7684 \\(j\\) \u8d21\u732e\u7ed9 \\(i\\) \u3002<\/p>\n<p>\u4e4b\u540e\u5c31\u662f\u7ef4\u62a4\u4e0b\u51f8\u58f3\u7684\u5e38\u89c4\u64cd\u4f5c\u3002\u5982\u679c<strong>\u961f\u5c3e\u4e24\u4e2a\u70b9\u7684\u76f4\u7ebf\u7684\u659c\u7387<\/strong> \u6bd4 <strong>\u6700\u540e\u4e00\u4e2a\u70b9\u548c\u5f53\u524d\u9700\u8981\u52a0\u5165\u7684\u70b9<\/strong>\u7684\u76f4\u7ebf\u7684\u659c\u7387\u8fd8<strong>\u5927<\/strong>\uff0c\u8bf4\u660e\u56fe\u5f62\u51f9\u8fdb\u53bb\u4e86\uff0c\u7531\u4e8e\u7ef4\u62a4\u7684\u662f\u4e0b\u51f8\u58f3\uff0c\u6240\u4ee5\u9700\u8981\u628a\u961f\u5c3e\u5143\u7d20\u5f39\u51fa\u76f4\u5230\u6ee1\u8db3\u6761\u4ef6\uff0c\u6700\u540e\u518d\u628a\u5f53\u524d\u70b9\u52a0\u5165\u3002<\/p>\n<p>\u6709\u51e0\u4e2a\u7ec6\u8282\u662f\u503c\u5f97\u6ce8\u610f\u7684\uff0c\u6bd4\u5982\u8981\u5148\u52a0\u5165 \\(f_0\\) \u8fd9\u4e2a\u51b3\u7b56\u70b9\uff0c\\(x_j=-w_{j+1}\\) \u7b49\u7b49\u3002<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"lang:default decode:true \">#include &lt;cstdio&gt;\r\n#include &lt;cstdlib&gt;\r\n#include &lt;cstring&gt;\r\n#include &lt;climits&gt;\r\n#include &lt;algorithm&gt;\r\n\r\n#define MAXBFN (1&lt;&lt;24)\r\nchar buffer[MAXBFN],*S,*T; \r\ninline char GetChar()  \r\n{\r\n    if(S==T)\r\n    {\r\n        T=(S=buffer)+fread(buffer,1,MAXBFN,stdin);\r\n        if(S==T)return EOF;\r\n    }\r\n    return *S++;\r\n}\r\n\r\n#define _min(_a,_b) ((_a)&lt;(_b)?(_a):(_b))\r\n#define _max(_a,_b) ((_a)&gt;(_b)?(_a):(_b))\r\n\r\ninline int getnum()\r\n{\r\n\tregister char c=GetChar();\r\n\twhile(!(c&gt;='0' &amp;&amp; c&lt;='9'))\r\n\t\tc=GetChar();\r\n\tregister int a=0;\r\n\twhile(c&gt;='0' &amp;&amp; c&lt;='9')\r\n\t{\r\n\t\ta*=10;a+=c-'0';\r\n\t\tc=GetChar();\r\n\t}\r\n\treturn a;\r\n}\r\n\r\nstruct _rect\r\n{\r\n\tint l,w;\r\n\tbool operator &lt; (const _rect&amp;oth)const\r\n\t{\r\n\t\treturn (l==oth.l?w&lt;oth.w:l&lt;oth.l);\r\n\t}\r\n}orect[1050505],rect[1050505];\r\n\r\nstruct _point\r\n{\r\n\tlong long x,y;\r\n\t_point operator - (const _point&amp;oth)const\r\n\t{\r\n\t\treturn (_point){x-oth.x,y-oth.y};\r\n\t}\r\n\tlong long operator * (const _point&amp;oth)const\r\n\t{\r\n\t\treturn (x*oth.y-y*oth.x);\r\n\t}\r\n}pnt[1050505];\r\nint front,rear;\r\n\r\nlong long f[1050505];\r\n\r\nint main()\r\n{\r\n\tregister int N=getnum();\r\n\tfor(register int i=1;i&lt;=N;i++)\r\n\t\torect[i].l=getnum(),orect[i].w=getnum();\r\n\t\r\n\tstd::sort(&amp;orect[1],&amp;orect[N+1]);\r\n\tregister int nN=0;\r\n\tfor(register int i=1;i&lt;=N;i++)\r\n\t{\r\n\t\twhile(nN &amp;&amp; rect[nN].w&lt;orect[i].w)\r\n\t\t\tnN--;\r\n\t\trect[++nN]=orect[i];\r\n\t}\r\n\tN=nN;\r\n\t\r\n\tpnt[rear++]=(_point){-rect[1].w,f[0]};\r\n\tfor(register int i=1;i&lt;=N;i++)\r\n\t{\r\n\t\t_point ts=(_point){1,rect[i].l};\r\n\t\twhile(front+1&lt;rear &amp;&amp; (pnt[front+1]-pnt[front])*ts&gt;=0)\r\n\t\t\tfront++;\r\n\t\tif(front&lt;rear)\r\n\t\t\tf[i]=pnt[front].y-(long long)pnt[front].x*rect[i].l;\r\n\t\t\r\n\t\t_point tn=(_point){-rect[i+1].w,f[i]};\r\n\t\twhile(front+1&lt;rear &amp;&amp; (pnt[rear-1]-pnt[rear-2])*(tn-pnt[rear-1])&lt;=0)\r\n\t\t\trear--;\r\n\t\tpnt[rear++]=tn;\r\n\t}\r\n\tprintf(\"%lld\\n\",f[N]);\r\n\t\r\n\treturn 0;\r\n}<\/pre>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>YZOJ P3669 [USACO2008 Mar]\u571f\u5730\u8d2d\u4e70 \u65f6\u95f4\u9650\u5236\uff1a1000MS \u5185\u5b58\u9650\u5236\uff1a262144K &hellip; <a href=\"https:\/\/0self.mnihyc.com\/blog\/archives\/806\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb<span class=\"screen-reader-text\">YZOJ P3669 [USACO2008 Mar]\u571f\u5730\u8d2d\u4e70<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[41,30,43],"tags":[],"class_list":["post-806","post","type-post","status-publish","format-standard","hentry","category-proa","category-otherdp","category-slopedp"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.1.1 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>YZOJ P3669 [USACO2008 Mar]\u571f\u5730\u8d2d\u4e70 - mnihyc&#039;s Blog<\/title>\n<meta name=\"description\" content=\"YZOJ P3669 \u571f\u5730\u8d2d\u4e70 \u65f6\u95f4\u9650\u5236\uff1a1000MS \u5185\u5b58\u9650\u5236\uff1a262144KB \u96be\u5ea6\uff1a \uff08\u81ea\u8bc4\uff09 \u9898\u76ee\u63cf\u8ff0 \u519c\u592b John \u51c6\u5907\u6269\u5927\u4ed6\u7684\u519c\u573a\uff0c\u4ed6\u6b63\u5728\u8003\u8651 (N) \uff08(1 leq N leq 1,000,000)\uff09 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