hihocoderWeekly236水路距离

#include   
#include  
const int MAXN = 800 + 10; 
const int dx[4] = {0, 0, 1, -1}; 
const int dy[4] = {1, -1, 0, 0}; 

int n, m;
char mp[MAXN][MAXN]; 
int ans[MAXN][MAXN], vis[MAXN][MAXN]; 
int q[MAXN*MAXN], dist[MAXN*MAXN]; 

bool Judge(int x, int y)
{
    if(x <0 || y <0 || x >= n || y >= m)
        return false; 
    if(vis[x][y] == 1 || mp[x][y] == ‘0‘)
        return false; 
    return true; 
}


int main(){ 
    //freopen("in.txt", "r", stdin); 

    while(scanf("%d %d", &n, &m) != EOF)
    {
        for(int i=0; i tail)
        {
            int q_t = q[tail]; 
            int dist_t = dist[tail++]; 
            int cx = q_t / MAXN, cy = q_t % MAXN; 
            for(int i=0; i<4; ++i)
            {
                int nx = cx + dx[i]; 
                int ny = cy + dy[i]; 
                if(Judge(nx, ny))
                {
                    q[head] = nx * MAXN + ny; 
                    dist[head++] = dist_t + 1; 
                    ans[nx][ny] = dist_t + 1; 
                    vis[nx][ny] = 1; 
                }
            }
        }

        for(int i=0; i