/* THE PROGRAM IS MADE BY PYY */
/*----------------------------------------------------------------------------//
Copyright (c) 2012 panyanyany All rights reserved.
URL : http://acm.hdu.edu.cn/showproblem.php?pid=1175
Name : 1175
Date : Thursday, April 05, 2012
Time Stage : 2 hours
Result:
5713239 2012-04-05 21:14:58 Accepted 1175
296MS 25372K 3624 B
C++ pyy
Test Data :
Review :
, AC ……
BFS DFS , DFS , ,
30 MS, BFS , MS, ,BFS DFS 。
,DFS , BFS 。 , ,
,DFS 5s , BFS , 1s, ,
2s, , 3s, 4s, …… 4s ,DFS 4 ,
BFS …… 。 ,
HDU , ……
//----------------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <vector>
#include <algorithm>
#include <iostream>
#include <queue>
using namespace std ;
#define MEM(a, v) memset (a, v, sizeof (a)) // a for address, v for value
#define max(x, y) ((x) > (y) ? (x) : (y))
#define min(x, y) ((x) < (y) ? (x) : (y))
#define INF (0x3f3f3f3f)
#define MAXN (1002)
#define DB /##/
#define LL __int64
#define _RANGE(a, b, e) ((b) <= (a) && (a) < e)
#define _IN(nd) (_RANGE((nd).x, 0, m) && _RANGE((nd).y, 0, n))
#define _MAP(nd) map[(nd).y][(nd).x]
#define _PATH(nd) path[(nd).y][(nd).x]
#define _VIS(nd) vis[(nd).y][(nd).x]
struct NODE {
int x, y, px, py;
int step;
int corn;
};
const int dir[4][2] = {0,1, 0,-1, 1,0, -1,0};
int n, m;
bool vis[MAXN][MAXN];
char map[MAXN][MAXN];
NODE beg, end, path[MAXN][MAXN];
void bfs()
{
int i;
queue<NODE> q;
NODE t, nt;
MEM(path, -1);
MEM(vis, 0);
beg.step = 0;
beg.corn = 0;
beg.px = beg.x;
beg.py = beg.y;
q.push(beg);
while (!q.empty())
{
t = q.front();
q.pop();
for (i = 0; i < 4; ++i)
{
nt = t;
if (t.corn == 2) // ……
{
i = 4;
if (nt.y > nt.py)
++nt.y;
else if (nt.y < nt.py)
--nt.y;
else if (nt.x > nt.px)
++nt.x;
else if (nt.x < nt.px)
--nt.x;
}
else
{
nt.y += dir[i][0];
nt.x += dir[i][1];
}
if (!_IN(nt) || ('0' != _MAP(nt) && _MAP(end) != _MAP(nt)))
continue;
/*
3 4
1 1 1 1
0 0 0 0
1 1 1 1
1
1 1 3 3
: (1,1)->..( )..->(1,3)->..->(3,3)
, , end ,
.
*/
if (_MAP(end) == _MAP(nt) && !(nt.x == end.x && nt.y == end.y))
continue;
if (nt.y == t.py && nt.x == t.px) //
continue;
if (nt.y != t.py && nt.x != t.px) //
{
nt.py = t.y;
nt.px = t.x;
++nt.corn;
}
else //
{
nt.py = t.y;
nt.px = t.x;
}
if (nt.corn >= 3 || (_VIS(nt) && nt.corn >= _PATH(nt).corn))
continue; // ,
DB printf ("nt:(%d,%d)<--(%d,%d) corn:%d step:%d
", nt.y, nt.x, \
nt.py, nt.px, nt.corn, nt.step);
++nt.step;
_PATH(nt) = nt;
_VIS(nt) = true;
if (nt.y == end.y && nt.x == end.x)
return ;
q.push(nt);
}
}
}
int main()
{
int i, j, q;
while (scanf("%d %d", &n, &m), n | m)
{
getchar();
for (j = 0; j < n; ++j)
{
for (i = 0; i < m; ++i)
{
scanf("%c", &map[j][i]);
getchar();
}
}
scanf("%d", &q);
for (i = 0; i < q; ++i)
{
scanf("%d %d %d %d", &beg.y, &beg.x, &end.y, &end.x);
--beg.y; --beg.x;
--end.y; --end.x;
if (!_IN(beg) || !_IN(end) || _MAP(beg) != _MAP(end) || '0' == _MAP(beg))
{
puts("NO");
continue;
}
if (beg.x == end.x && beg.y == end.y)
{
puts("YES");
continue;
}
bfs();
if (0 <= _PATH(end).corn && _PATH(end).corn <= 2)
puts("YES");
else
printf ("NO
");
}
}
return 0;
}