[USACO] Lake Counting
【题目描述】
Due to recent rains, water has pooled in various places in Farmer John's field, which is represented by a rectangle of N x M (1 <= N <= 100; 1 <= M <= 100) squares. Each square contains either water ('W') or dry land ('.'). Farmer John would like to figure out how many ponds have formed in his field. A pond is a connected set of squares with water in them, where a square is considered adjacent to all eight of its neighbors.
Given a diagram of Farmer John's field, determine how many ponds he has.
输入
* Line 1: Two space-separated integers: N and M
* Lines 2..N+1: M characters per line representing one row of Farmer John's field. Each character is either 'W' or '.'. The characters do not have spaces between them.
输出
* Line 1: The number of ponds in Farmer John's field.
【题目分析】
一道简单的深搜...先创建一个bool类型的数组b,是'.'就放0,是'W'就放1....统计能组成正方形的W的个数就行...
z#include<bits/stdc++.h> bool b[101][101]; char a[101][101]; void dfs(int i,int j) { if(b[i][j]!=0) { b[i][j]=0; if(b[i][j-1]!=0) dfs(i,j-1); if(b[i][j+1]!=0) dfs(i,j+1); if(b[i-1][j]!=0) dfs(i-1,j); if(b[i+1][j]!=0) dfs(i+1,j); if(b[i-1][j-1]!=0) dfs(i-1,j-1); if(b[i-1][j+1]!=0) dfs(i-1,j+1); if(b[i+1][j-1]!=0) dfs(i+1,j-1); if(b[i+1][j+1]!=0) dfs(i+1,j+1); } return ; } int main() { int m,n,ans=0; scanf("%d %d\n",&m,&n); int i,j; for(i=1;i<=m;i++) { for(j=1;j<=n;j++) { scanf("%c",&a[i][j]); if(a[i][j]=='W')b[i][j]=1; } getchar(); } for(i=0;i<=m;i++) for(j=0;j<=n;j++) { if(b[i][j]) { dfs(i,j); ans++; } } printf("%d",ans); return 0; }