A. Appleman and Easy Task
time limit per test
1 secondmemory limit per test
256 megabytes input
standard input
output
standard output
Toastman came up with a very easy task. He gives it to Appleman, but Appleman doesn‘t know how to solve it. Can you help him?
Given a n × n checkerboard. Each cell of the board has either character ‘x‘, or character ‘o‘. Is it true that each cell of the board has even number of adjacent cells with ‘o‘? Two cells of the board are adjacent if they share a side.
Input
The first line contains an integer n (1 ≤ n ≤ 100). Then n lines follow containing the description of the checkerboard. Each of them contains n characters (either ‘x‘ or ‘o‘) without spaces.
Output
Print "YES" or "NO" (without the quotes) depending on the answer to the problem.
Sample test(s)
input
3
xxo
xox
oxx
output
YES
input
4
xxxo
xoxo
oxox
xxxx
output
NO
解题：暴力枚举即可。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 #include <algorithm> 6 #include <climits> 7 #include <vector> 8 #include <queue> 9 #include <cstdlib> 10 #include <string> 11 #include <set> 12 #include <stack> 13 #define LL long long 14 #define pii pair<int,int> 15 #define INF 0x3f3f3f3f 16 using namespace std; 17 const int maxn = 110; 18 int n; 19 char mp[maxn][maxn]; 20 const int dir[4][2] = {0,-1,0,1,-1,0,1,0}; 21 int main() { 22 int ans; 23 bool flag; 24 while(~scanf("%d",&n)){ 25 getchar(); 26 memset(mp,‘x‘,sizeof(mp)); 27 for(int i = 1; i <= n; i++){ 28 for(int j = 1; j <= n; j++) 29 mp[i][j] = getchar(); 30 getchar(); 31 } 32 flag = true; 33 for(int i = 1; i <= n; i++){ 34 for(int j = 1; j <= n; j++){ 35 ans = 0; 36 for(int k = 0; k < 4; k++){ 37 int x = i+dir[k][0]; 38 int y = j+dir[k][1]; 39 if(mp[x][y] == ‘o‘) ans++; 40 } 41 if(ans&1) {flag = false;break;} 42 } 43 } 44 flag?puts("YES"):puts("NO"); 45 } 46 return 0; 47 }