题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3781 Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are called connected if they share an edge and they are in…

Paint the Grid Reloaded Time Limit: 2 Seconds      Memory Limit: 65536 KB Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are called connected if they share an edge and they are…

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=5268 题目大意:字符一样并且相邻的即为连通.每次可翻转一个连通块X(O)的颜色,问至少改变几次使得图上所有字符都相等. 解题思路: 1) dfs( 建图 ) ,因为翻转的时候每翻转连通块中一个整个连通块都翻转,这样你可以将其看成一个有边相连的无向图,每个边的两个顶点颜色都不一样. 2) bfs( 寻找最优解 ) , 建完图后就需要翻转计算最优解,可以枚举从每一点开始…

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3781 Time Limit: 2 Seconds      Memory Limit: 65536 KB Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are calle…

LINK:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3781 题意:n*m只由OX组成的矩阵,可以选择某一连通块变成另一个字符,问整个矩阵变成相同的最小次数 思路:对所有连通块编号,根据是否与其他联通块相连建边,最后得到图后枚举以某起点(代表某连通块)所能到的最大距离求它们的最小值即可. 关键还是在于模型的转换,这方面我好像有点欠缺orz /** @Date : 2017-03-30-15.09 * @Author…

题目大意: 给一个n*m的X O构成的格子,对一个点操作可以使与它相连通的所有一样颜色的格子翻转颜色(X—>O或O—>X),问给定的矩阵最少操作多少次可以全部变成一样的颜色. 思路: 1.每次操作都将本身所在的连通块与和自己相邻的不同颜色的连通块变成同一种颜色,也就是变成一个连通块了,那么要使n次操作后全部变成一样的颜色,也就是从某点出发到达其余所有点. 2.因此dfs把连通块缩成点,然后相邻的连通块之间建边,枚举以每个点为根的情况,bfs求出每种情况的深度,取最小的即为答案. 反思: 1.h…

枚举,$BFS$,连通块缩点. 可以枚举一开始染哪个位置,然后逐层往外染色,看最多需要多少操作次数,也就是算最短距离.连通块缩点之后可以保证是一个黑白相间的图,且每条边的费用均为$1$,$BFS$即可. #include<cstdio> #include<queue> #include<algorithm> #include<vector> #include<cstring> using namespace std; int T,n,m; ][]…

Leo has a grid with N rows and M columns. All cells are painted with either black or white initially. Two cells A and B are called connected if they share an edge and they are in the same color, or there exists a cell C connected to both A and B. Leo…

Paint the Grid Again Time Limit: 2 Seconds      Memory Limit: 65536 KB Leo has a grid with N × N cells. He wants to paint each cell with a specific color (either black or white). Leo has a magical brush which can paint any row with black color, or an…

Knight Moves Time Limit: 2 Seconds      Memory Limit: 65536 KB A friend of you is doing research on the Traveling Knight Problem (TKP) where you are to find the shortest closed tour of knight moves that visits each square of a given set of n squares…