http://codeforces.com/problemset/problem/540/C You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend one level lower and the only way to do this is to fall through the…

链接:http://codeforces.com/problemset/problem/540/C You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend one level lower and the only way to do this is to fall through…

题目传送门 /* 题意:告诉起点终点,踩一次, '.'变成'X',再踩一次,冰块破碎,问是否能使终点冰破碎 DFS:如题解所说,分三种情况:1. 如果两点重合,只要往外走一步再走回来就行了:2. 若两点相邻, 那么要不就是踩一脚就破了或者踩一脚走开再走回来踩一脚破了:3. 普通的搜索看是否能到达, 若能还是要讨论终点踩几脚的问题:) DFS 耗时大,险些超时,可以用BFS来做 */ #include <cstdio> #include <algorithm> #include &l…

ice(USACO) Description Bessie 在一个冰封的湖面上游泳,湖面可以表示为二维的平面,坐标范围是-1,000,000,000..1,000,000,000. 湖面上的N(1 <= N <= 20,000)个位置有石块(编号分别为1到N),其它位置是冰面. 由于Bessie滑冰技术不够好,她通过推动自己旁边的石块,依靠反作用力向某一个方向前进,在碰到一个新的石块之前,Bessie是不会停下来的.(当然,最后会停留在某块石块的前一个格子里)由于Bessie无法计算复杂的角度…

http://codeforces.com/problemset/problem/540/C       Ice Cave Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 540C Description You play a computer game. Your character stands on some lev…

C. Ice Cave Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/C Description You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend…

方法:从根节点开始广搜,如果遇到了应该删除的点,就再广搜删掉它的子树并标记,然后统计一下被标记的个数就是答案,所谓技巧就是从根节点开始搜索的时候,如果遇到了某个节点的距离<0,就让它是0,0可以消除负数效应,让后面的点重新参与正常删除操作,这个方法的正确性不难证明,可以自己画一下图.而且还有比较方便的方法就是,记录不被删除的点,然后n-他们就可以了. 代码如下: #include<iostream> #include<cstdio> #include<cstring&g…

题目链接:https://vjudge.net/contest/226823#problem/C You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend one level lower and the only way to do this is to fall through t…

要点 题意:可以拐弯,即哈密顿距离 注意不可以直接一个一个搜,这过程中会把下一轮的标记上,导致同一轮的其它点没能正常完成应有的搜索 因此采用双层广搜,把同一轮先都出队列再的一起搜 #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <vector> #include <queue> #include <cct…

J - Two Buttons Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 520B Description Vasya has found a strange device. On the front panel of a device there are: a red button, a blue button a…