求助,RE+WA

RT

#include <iostream>
#include <cstdio>
#include <algorithm>
#define MAXV 1010
using namespace std;

//rt
int n;
int x1, y1, x2, y2;
bool mapper[ MAXV] [ MAXV];

//bfs
struct zb
{
    int x, y;
    int jl;
} queue [ 10001100];
int l, r;
int dx [ 5] = { 0, 1, -1, 0, 0}, dy [ 5] = { 0, 0, 0, 1, -1};

//main
int main ( )
{
    //sr
    cin>> n;
    for ( int i = 1; i <= n; i ++)
    {
        string a;
        cin>> a;
        for ( int j = 1; j <= n; j ++)
        {
            if ( a [ j] == '1')
            {
                mapper [ i] [ j] = 1;
            }
            else
            {
                mapper [ i] [ j] = 0;
            }
        }
    }
    cin>> x1>> x2>> y1>> y2;

    //bfs
    l = 1;r = 2;
    queue [ 1] = { x1, x2, 0};
    mapper [ x1] [ x2] = 1;
    while ( l < r)
    {
        zb now = queue [ l];
        l ++;
        if ( now. x == x2 && now. y == y2)
        {
            printf ( "%d\n", now. jl); 
            return 0;
        }

        for ( int i = 1; i <= 4; i ++)
        {
            if ( ! mapper [ dx [ i] + now. x] [ dy [ i] + now. y])
            {
                mapper [ dx [ i] + now. x] [ dy [ i] + now. y] = 1;
                queue [ r ++] = { dx [ i] + now. x, dy [ i] + now. y, now. jl + 1};
            }
        }
    }
}