我在dev能过在洛谷过不了，为什么啊

#include<bits/stdc++.h>
using namespace std;

int mp[105][105],n,dx[4] = {0,0,-1,1},dy[4] = {1,-1,0,0},x1,y1,ansx,ansy;
struct zuobiao
{
    int x,y;
};

void bfs(int x,int y)
{
    queue<zuobiao> q;
    q.push({x,y});
    mp[x][y] = 1;
    while(q.size())
    {
        auto u = q.front();
        q.pop();
        for(int i = 0;i < 4;i++)
        {
            int a = u.x + dx[i],b = u.y + dy[i];
            if(mp[a][b] != 0||a > n||b > n||a < 1||b < 1)
            {
                continue;
            } 
            mp[a][b] = mp[u.x][u.y] + 1;
            q.push({a,b});
        }
    }
}

int main()
{
    cin >> n;
    for(int i = 1;i <= n;i++)
    {
        for(int j = 1;j <= n;j++)
        {
            char c;
            cin >> c;
            if(c == '0')
            {
                mp[i][j] = 0;
            }
            else 
            {
                mp[i][j] = 1;
            }
        }
    }
    cin >> x1 >> y1 >> ansx >> ansy;
    bfs(x1,y1);
    cout << mp[ansx][ansy] - 1;
    return 0;
}