记忆化(求赞)

#include<bits/stdc++.h>
using namespace std;
int a[210][210];
int xx[4] = {-1,0,1,0},yy[4] = {0,1,0,-1},ans;
int f[210][210];
int n,m;
int dfs(int x,int y){
    if(f[x][y])return f[x][y];
    for(int i=0;i<4;i++){
        int nx = xx[i]+x,ny = yy[i]+y;
        if(nx<1||ny<1||nx>n||ny>m)continue;
        if(a[nx][ny]<a[x][y]){
            f[x][y] = max(f[x][y],dfs(nx,ny));
        }
    }
    return f[x][y]+=1;
}
int main(){
    cin >> n >> m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin >> a[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            if(f[i][j]==0){
                ans = max(dfs(i,j),ans);
            }
        }
    }
    cout << ans;
    return 0;
}