CSU 1080: A simple maze

典型的bfs。

代码如下：

#define MAXN 55
#define INF 0x7fffffff
#include<stdio.h>
#include<string.h>
int T, N, M, Sr,Sc,Er,Ec, min;
char s[MAXN][MAXN], vis[MAXN][MAXN];
int q[MAXN*MAXN], dis[MAXN][MAXN];
int dx[4] = {0,0,-1,1};
int dy[4] = {1,-1,0,0};
void solve(int x, int y)
{
    min = INF;
    memset(vis,0,sizeof(vis));
    memset(dis,0,sizeof(dis));
    int front = 0, rear = 0;
    int u = (x-1)*M + y;
    vis[x][y] = 1; dis[x][y] = 0;
    q[rear++] = u;
    while(front < rear)
    {
        u = q[front++];//printf("...u==%d\n",u);
        y = u%M;
        if(y==0) y = M;
        x = (u-y)/M + 1;//    printf("...x=%d y=%d\n",x,y);
        for(int i = 0; i < 4; i ++)
        {
            int nx = x+dx[i], ny = y+dy[i];
            if(nx>0 && nx<N+1 && ny>0 && ny<M+1 )
            {
                if('1'-s[nx][ny] && !vis[nx][ny])
                {
                    int v = (nx-1)*M + ny;//printf("v==%d\n",v);
                    q[rear++] = v;
                    vis[nx][ny] = 1;
                    dis[nx][ny] = dis[x][y] + 1;
                }
            }
            if(u == (Er-1)*M+Ec && dis[x][y] < min) min = dis[x][y];
        }
    }
    if(min == INF)printf("No Path.\n");
    else printf("%d\n",min);
}
void input()
{
    while(scanf("%d",&T) == 1)
        while(T --)
        {
            scanf("%d%d",&N, &M);
            scanf("%d%d%d%d",&Sr,&Sc,&Er,&Ec);
            for(int i = 1; i <= N; i ++)
                scanf("%s",s[i]+1);
            solve(Sr,Sc);
        }
}
int main()
{
    input();
    return 0;
}