广搜_限制转弯次数[连连看](HDU_1175)

#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;
}