https://111qqz.com/en/tags/%E6%9C%80%E7%9F%AD%E8%B7%AF/Recent content in 最短路 on 111qqz's blogHugo -- gohugo.ioen© 2015-2026 111qqzMon, 18 Jul 2016 12:20:08 +0000https://111qqz.com/en/post/acm-icpc/2016/2016-07-18-cf689b/Mon, 18 Jul 2016 12:20:08 +0000https://111qqz.com/en/post/acm-icpc/2016/2016-07-18-cf689b/<p><a href="http://codeforces.com/problemset/problem/689/B" target="_blank" rel="noreferrer">cf689B题目链接</a></p> <p>题意：n点。。点i到点j的代价是|i-j|..给出n条近路。。。a[i]表示点i到a[i]的代价为1（注意近路不一定就近）</p>https://111qqz.com/en/post/acm-icpc/2016/2016-07-14-hdu-3873/Thu, 14 Jul 2016 17:25:24 +0000https://111qqz.com/en/post/acm-icpc/2016/2016-07-14-hdu-3873/<p><a href="http://acm.hdu.edu.cn/showproblem.php?pid=3873" target="_blank" rel="noreferrer">hdu3873题目链接</a></p> <p>题意：n个点的图。。。每个点可能被若干其他点保护。。。被保护的意思是。。。如果想访问某个点。。那么必须先访问保护该点的所有点。。。问从点1到点n的最小代价。。</p>https://111qqz.com/en/post/acm-icpc/2016/2016-07-06-bzoj-1681-usaco2005-marchecking-an-alibi-e4b88de59ca8e59cbae79a84e8af81e6988e-spfa/Wed, 06 Jul 2016 13:18:30 +0000https://111qqz.com/en/post/acm-icpc/2016/2016-07-06-bzoj-1681-usaco2005-marchecking-an-alibi-e4b88de59ca8e59cbae79a84e8af81e6988e-spfa/<h2 class="relative group">1681: [Usaco2005 Mar]Checking an Alibi 不在场的证明 <div id="1681-usaco2005-marchecking-an-alibi-不在场的证明" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#1681-usaco2005-marchecking-an-alibi-%e4%b8%8d%e5%9c%a8%e5%9c%ba%e7%9a%84%e8%af%81%e6%98%8e" aria-label="Anchor">#</a> </span> </h2> <p>Time Limit: 5 Sec  Memory Limit: 64 MB Submit: 250  Solved: 178 [<a href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=1681" target="_blank" rel="noreferrer">Submit</a>][<a href="http://www.lydsy.com/JudgeOnline/problemstatus.php?id=1681" target="_blank" rel="noreferrer">Status</a>][<a href="http://www.lydsy.com/JudgeOnline/bbs.php?id=1681" target="_blank" rel="noreferrer">Discuss</a>]</p>https://111qqz.com/en/post/acm-icpc/2016/2016-05-21-bzoj-1631/Sat, 21 May 2016 13:09:57 +0000https://111qqz.com/en/post/acm-icpc/2016/2016-05-21-bzoj-1631/<h2 class="relative group">1631: [Usaco2007 Feb]Cow Party <div id="1631-usaco2007-febcow-party" class="anchor"></div> <span class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none"> <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#1631-usaco2007-febcow-party" aria-label="Anchor">#</a> </span> </h2> <p>Time Limit: 5 Sec  Memory Limit: 64 MB Submit: 670  Solved: 493 [<a href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=1631" target="_blank" rel="noreferrer">Submit</a>][<a href="http://www.lydsy.com/JudgeOnline/problemstatus.php?id=1631" target="_blank" rel="noreferrer">Status</a>][<a href="http://www.lydsy.com/JudgeOnline/bbs.php?id=1631" target="_blank" rel="noreferrer">Discuss</a>]</p>https://111qqz.com/en/post/acm-icpc/2015/2015-12-22-cf602c/Tue, 22 Dec 2015 09:01:18 +0000https://111qqz.com/en/post/acm-icpc/2015/2015-12-22-cf602c/<p><a href="http://codeforces.com/problemset/problem/602/C" target="_blank" rel="noreferrer">http://codeforces.com/problemset/problem/602/C</a> 题意：给出n个城镇，m条双向铁路，对于任意不同的x,y，如果x,y之间没有铁路，那么一定有双向公路。train只能走铁路，bus只能走公路。现在一辆火车和一辆bus同时从1出发，要到达n，处于安全考虑，bus和火车不能同时处在除了n以外的点。bus和train不要求同时到达。任意一段道路的时间花费都是1小时。问最少需要多久使得bus和train都到达n。如果存在某个不能到达，那么输出-1. 思路：n才400.一开始打算先按照rail和road建两个图。这两个图互为补。然后在floyd的时候加以判断。但是马上就发现。。不能同时到达同伙一个点这个条件其实不会影响。。因为按照题意，一定存在一条1到n的路，不是公路就是铁路。那么就让有路的花费1的代价到n，然后剩下的求一个一到n的最短路即可。由于n才400.。最短路怎么搞都行。。我偷懒就用floyd了。</p>