广搜_限制转弯次数[连连看](HDU_1175)

标准广搜限制转弯次数

同 广搜_限制转弯次数(HDU_1728)

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

#define M 1002

struct node {
    int x,y,turn;
    node(int _x,int _y,int _turn)
    {
        x = _x; y = _y; turn = _turn;
    }
};

int map[M][M],flag[M][M];
int move[4][2] = {-1,0,0,1,1,0,0,-1};
queue<node> q;
int n,m;

int judge(int x,int y)
{
    if(x<1 || x>n || y<1 || y>m || map[x][y])    return 0;
    return 1;
}

int bfs(int x1,int y1,int x2,int y2)
{
    memset(flag,0,sizeof(flag));
    while(!q.empty())
    {
        q.pop();
    }
    q.push(node(x1,y1,0));
    flag[x1][y1] = 1;
    while(!q.empty())
    {
        int turn = q.front().turn;
        if(q.front().turn > 2)    return 0;
        for(int i=0; i<4; i++)
        {
            int dx = q.front().x + move[i][0];
            int dy = q.front().y + move[i][1];
            
            while(judge(dx,dy) || dx == x2 && dy == y2)
            {
                if(dx == x2 && dy == y2 && map[dx][dy] == map[x1][y1])
                    return 1;
                if(!flag[dx][dy])
                {
                    flag[dx][dy] = 1;
                    q.push(node(dx,dy,turn + 1));
                }
                dx += move[i][0];
                dy += move[i][1];
            }
        }
        q.pop();
    }
    return 0;
}

int main(int argc, char* argv[])
{
#ifdef __MYLOCAL
    freopen("in.txt","r",stdin);
#endif
    
    int q,x1,x2,y1,y2;
    while(scanf("%d%d",&n,&m) && n+m)
    {
        for(int i=1; i<=n; i++)
        {
            for(int j=1; j<=m; j++)
                scanf("%d",&map[i][j]);
        }
        scanf("%d",&q);
        while(q--)
        {
            scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
            
            if(x1 == x2 && y1 == y2 || map[x1][y1] != map[x2][y2] || !map[x1][y1] || !map[x2][y2])
            {
                printf("NO\n");
            }
            else
            {
                printf("%s\n",bfs(x1,y1,x2,y2) ? "YES" : "NO"); 
            }
        }
    }
    
    return 0;
}