能跑起来但不输出

数组未越界

开的是全局变量

#include<bits/stdc++.h>
using namespace std;
const int Maxn=1000+6; 
int a[Maxn][Maxn]={0};
struct P{
	int flag[Maxn][Maxn];
	int x;
	int y;
};
queue<P> q;
int go[2][2]={{1,0},{0,1}};
int ma_x,ma_y,end_x,end_y;
int maxv=0;
int ans=0;
int bfs()
{
    cout << "hah"<<endl;
	P start;
	start.flag[Maxn][Maxn]={0};
	start.flag[0][0]=1; 
	start.flag[ma_x][ma_y]=1;
	if(ma_x>=2 && ma_y>=1)
    start.flag[ma_x-2][ma_y-1]=1;
    if(ma_x>=1 && ma_y>=2)
    start.flag[ma_x-1][ma_y-2]=1;
    if(ma_y>=2)
    start.flag[ma_x+1][ma_y-2]=1;
    if(ma_y>=1)
    start.flag[ma_x+2][ma_y-1]=1;
    
    start.flag[ma_x+2][ma_y+1]=1;
    
    start.flag[ma_x+1][ma_y+2]=1;
    if(ma_x>=1)
    start.flag[ma_x-1][ma_y+2]=1;
    if(ma_x>=2)
    start.flag[ma_x-2][ma_y+1]=1;
	start.x = 0;
	start.y = 0;
	
	q.push(start);
	while(!q.empty())
	{
		P be;
		
		be = q.front();
		q.pop();
		
		for(int i=0;i<2;i++)
		{ 
		    
			be.x = be.x + go[i][0];
			be.y = be.y + go[i][1];
			if(be.x>end_x||be.y>end_y||be.flag[be.x][be.y])
			continue;
			be.flag[be.x][be.y]=1;
			q.push(be);
			if(be.x == end_x && be.y == end_y) ans++;
		}
	}
	
	return 0;
}
int main()
{   '
   cin >> end_x >> end_y >> ma_x >> ma_y ;
   bfs();
   cout << ans;
   return 0;
}