这是我的BFS代码

#include <iostream>
#include <queue>

using namespace std;

#define int long long
#define TRACE 1
#define tcout TRACE && cout
#define el printf("\n")
#define inf 0x7fffffff

int n, m;
int a[110][110];
int ans[10000010];
int cnt;
int x1, y1, x2, y2;
int maxn = -inf, minn = inf;
int res = -inf;

struct Node{
	int x, y, s;
	Node(){
		
	}
	Node(int _x, int _y, int _s){
		x = _x;
		y = _y;
		s = _s;
	}
};

int fx[] = {-1, 0, 0, 1};
int fy[] = {0, -1, 1, 0};

queue<Node> q;

void bfs(int x, int y){
	q.push(Node(x, y, 0));
	
	while(!q.empty()){
		int x = q.front().x;
		int y = q.front().y;
		int s = q.front().s;
		
		q.pop();
		
		if(x == x2 && y == y2){
			ans[++cnt] = s+1;
		}
		
		for(int i=0; i<4; i++){
			int dx = x + fx[i];
			int dy = y + fy[i];
			if(dx >= 1 && dy >= 1 && dx <= n && dy <= m){
				if(a[dx][dy] < a[x][y]){
					q.push(Node(dx, dy, s+1));
				}
			} 
		}
	}
}

signed main()
{
	cin >> n >> m;
	for(int i=1; i<=n; i++){
		for(int j=1; j<=m; j++){
			cin >> a[i][j];
			if(a[i][j] > maxn){
				maxn = a[i][j];
				x1 = i, y1 = j;
			}
			if(a[i][j] < minn){
				minn = a[i][j];
				x2 = i, y2 = j;
			}
		}
	}
	bfs(x1, y1);
	for(int i=1; i<=cnt; i++){
		res = max(res, ans[i]);
	}
	cout << res;
	el;
	return 0;
}

这是我的提交记录

向大佬们求助！！