### 题目大意: 在一个 $n * m$ 的矩阵中,有空地.坏人.好人和墙.你可以将空地变成墙来堵住坏人.$(n, m)$为出口,是否存在一个方案使得矩阵中所有好人能够走到出口,而所有坏人不能通过出口,相应的输出$Yes$ 和 $No$. ### 思路: 1.预处理:如果坏人和好人相邻,那么坏人一定可以走到隔壁好人,再通过好人的路径走到终点,所以不符合, 输出$No$; ​ 如果当前方格为坏人,我们只有将他四周都堵住,他才能不会走到出口, 即将周围空地变成墙. 2.试想一下,如何挨个判断好人是…

这题犯了一个很严重的错误,bfs 应该在入队操作的同时标记访问,而不是每次只标记取出的队首元素. 题目链接:https://codeforces.com/contest/1365/problem/D 题意 有一个 $n \times m$ 的迷宫,迷宫有四种方格: '.' 空方格 '#' 墙 'B' 坏人 'G' 好人 人与人间可以通行,人与墙间不能,可以把任意空方格变为墙,问能否所有好人可以到达 $(n, m)$ 但所有坏人不能. 题解 无解有两种情况: 坏人与好人相邻 在每个坏人相邻的四个方…

D - Infinite Maze We've got a rectangular n × m-cell maze. Each cell is either passable, or is a wall (impassable). A little boy found the maze and cyclically tiled a plane with it so that the plane became an infinite maze. Now on this plane cell (x,…

[题目链接]:http://codeforces.com/problemset/problem/196/B [题意] 给你一个n*m的棋盘; 然后你能够无限复制这个棋盘; 在这个棋盘上你有一个起点s; 然后问你,你能不能从这个起点s开始一直走无限远; [题解] 考虑两个不同棋盘上的点(x1,y1),(x2,y2)(即复制出的另外一个棋盘); 假设他们在第一个棋盘上对应的投影x%n,y%m是相同的; 且它们都能由起点S到达; 即S能到达这两个点; 则可知; 可以从S到达其中的一个点(x1,y1);…

#include <stdio.h> #include <string.h> #include <iostream> #include <string> #include <math.h> #include <algorithm> #include <vector> #include <stack> #include <queue> #include <set> #include <…

这道题目甚长, 代码也是甚长, 但是思路却不是太难.然而有好多代码实现的细节, 确是十分的巧妙. 对代码阅读能力, 代码理解能力, 代码实现能力, 代码实现技巧, DFS方法都大有裨益, 敬请有兴趣者耐心细读.(也许由于博主太弱, 才有此等感觉). 题目: UVa 1103 In order to understand early civilizations, archaeologists often study texts written in  ancient languages. One…

Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu Submit Status Practice UVA 816 Appoint description:   Description  Abbott’s Revenge  The 1999 World Finals Contest included a problem based on a “dice maze.” At the time the probl…

Abbott's Revenge Time limit: 3.000 seconds Abbott’s Revenge  Abbott’s Revenge The 1999 World FinalsContest included a problem based on a “dicemaze.” At the time the problem was written, the judges were unable todiscover the original source of the dic…

Problem UVA10384-The Wall Pushers Accept: 199   Submit: 1546Time Limit: 10000 mSec Problem Description Input The input file may contain several mazes to solve. Each maze description starts with a single line containing two integers x and y (1 ≤ x ≤ 6,…

1 .Preface /** * There have been many data to introduce the algorithm. So I will try to simply explain it and explain the program in detail. */ /** * Prerequisites: *  1). a survival skill in CPP programing language. *  2). a curious mind for maze pr…