零分代码求调！

#include <bits/stdc++.h> // x y means x hang y lie
using namespace std;
int dx[4]{0,0,-1,1}; //up down left right
int dy[4]{-1,1,0,0}; //up down left right
int mmap[105][105]{};
int remember[105][105]{}; //remember data
int m{},n{}; //first input n!
int dfs(int x,int y)
{
	if(remember[x][y]) return remember[x][y];//return the memory
	//not be found yet
	remember[x][y] = 1;//init
	for(int i{};i<4;i++)// four directions
	{
		int nx = x+dx[i]; // next x
		int ny = y+dy[i]; // next y
		if(nx>0 && ny>0 && nx<=n && ny<=m/*check not go out*/ && mmap[nx][ny] < mmap[x][y]/*lower(must) than now place*/)
		{
			//ok
			//notice
			dfs(nx,ny);
			remember[x][y] = max(remember[x][y], remember[nx][ny]+1);
		}
	}
	return remember[x][y];
}
int main()
{
	int ans;
	cin>>n>>m;
	for(int i{1};i<=n;i++)
	{
		for(int j{1};j<=m;j++)
		{
			cin>>mmap[i][j];
		}
	}
	for(int i{1};i<=n;i++)
	{
		for(int j{1};j<=m;j++)
		{
			ans = max(ans,dfs(i,j));
		}
	}
	cout<<ans;
	return 0;
}