#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int dx[4] = { 0,0,1,-1 };
int dy[4] = { 1,-1,0,0 };
int n, m, a[201][201], s[201][201], ans;
int dfs(int x, int y) {
    if (s[x][y])return s[x][y];//记忆化搜索
    s[x][y] = 1;//题目中答案是有包含这个点的
    for (int i = 0; i < 4; i++)
    {
        int xx = dx[i] + x;
        int yy = dy[i] + y;//四个方向
        if (xx > 0 && yy > 0 && xx <= n && yy <= m && a[x][y] > a[xx][yy]) {
            dfs(xx, yy);
            s[x][y] = max(s[x][y], s[xx][yy] + 1);
        }
    }
    return s[x][y];
}
int main()
{
    scanf("%d%d", &n, &m);//同题目的R,C
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            scanf("%d", &a[i][j]);
    for (int i = 1; i <= n; i++)//找从每个出发的最长距离
        for (int j = 1; j <= m; j++)
            ans = max(ans, dfs(i, j));//取最大值
    printf("%d", ans);
    return 0;
...