POJ 3620 Avoid The Lakes

http://poj.org/problem?id=3620

DFS

从任意一个lake出发

重置联通的lake 并且记录 更新ans

 #include <iostream>
 #include <string.h>
 #include <stdio.h>
 using namespace std;

 int N,M,K;
 bool pool[][];
 int d[][] = {-, , , , , , , -};
 int res = ;
 int ans = ;
 bool OK(int x, int y)
 {
     if (x <  || x > N || y <  || y > M) return false;
     return pool[x][y];
 }
 void dfs(int x, int y)
 {
     res++;
     pool[x][y] = false;
     int nx, ny;
     for (int i = ; i < ; i++)
     {
         nx = x+d[i][];
         ny = y+d[i][];
         if ( OK(nx, ny) )
         {
             dfs(nx, ny);
         }
     }
 }
 int main()
 {     while (cin >> N >> M >> K)
     {
         memset(pool, , sizeof(pool));
         for (int i = ; i < K; i++)
         {
             int r, c;
             scanf("%d%d", &r, &c);
             pool[r][c] = true;
         }
         res = ;
         ans = ;
         for (int i = ; i <= N; i++)
         for (int j = ; j <= M; j++)
         {
           if (OK(i, j))
           {
               res = ;
               dfs(i, j);
           }
           ans = max(ans, res);
         }
         cout << ans << endl;
     }
     return ;
 }