HDU 6113 度度熊的01世界（dfs）

#include<bits/stdc++.h>
using namespace std;

const int N = 105;
char s

;
int vis

;
int dx[4] = {1,-1,0,0};
int dy[4] = {0,0,1,-1};
int n,m;

void dfs(int x,int y)
{
vis[x][y] = 1;
for(int i = 0;i < 4;i++)
{
int tx = x + dx[i];
int ty = y + dy[i];
if(!vis[tx][ty] && (tx >= 0 && tx <= n+1 && ty >= 0 && ty <= m+1))
{
if(s[x][y] == s[tx][ty])
dfs(tx,ty);
}
}
}

int main()
{

while(~scanf("%d%d",&n,&m))
{
for(int i = 1;i <= n;i++)
scanf("%s",s[i]+1);

for(int i = 0;i <= n+1;i++)
s[i][0] = s[i][m+1] = '0';
for(int i = 0;i <= m+1;i++)
s[0][i] = s[n+1][i] = '0';

memset(vis,0,sizeof(vis));
int sum1 = 0,sum0 = 0;
for(int i = 0;i <= n+1;i++)
for(int j = 0;j <= m+1;j++)
{
if(vis[i][j])
continue;
if(s[i][j] == '1')
sum1++;
if(s[i][j] == '0')
sum0++;
dfs(i,j);
}
if(sum1 != 1)
{
printf("-1\n");
continue;
}
if(sum0 == 1)
printf("1\n");
else if(sum0 == 2)
printf("0\n");
else
printf("-1\n");
}
return 0;
}