具体思路就是将高度从大到小排序，然后从高处开始dp，这样可以保证无后效性

#include<bits/stdc++.h>
using namespace std;

struct node {
	int x;
	int y;
	int num;
}a[110];
int f[110][110] , g[110][110] , n , m;

bool cmp(node a1 , node a2) {
	if(a1.num == a2.num) return a1.x < a2.x;
	return a1.num > a2.num;
}

void init() {
	cin >> n >> m;
	for(int i = 1; i <= n; i ++)
	for(int j = 1; j <= m; j ++) {
		cin >> g[i][j];
		f[i][j] = 1;
		int k = (i - 1) * m + j; 
		a[k].x = i;
		a[k].y = j;
	    a[k].num = g[i][j];
	}
	sort(a + 1 , a + n * m + 1 , cmp);
}

void dp() {
	for(int k = 1; k <= n * m; k ++) {
		int i = a[k].x , j = a[k].y;
		if(g[i + 1][j] > g[i][j]) f[i][j] = max(f[i + 1][j] + 1 , f[i][j]);
		if(g[i - 1][j] > g[i][j]) f[i][j] = max(f[i - 1][j] + 1 , f[i][j]);
		if(g[i][j + 1] > g[i][j]) f[i][j] = max(f[i][j + 1] + 1 , f[i][j]);
		if(g[i][j - 1] > g[i][j]) f[i][j] = max(f[i][j - 1] + 1 , f[i][j]);
	}
	int ans = -1;
	for(int i = 1; i <= n; i ++)
	for(int j = 1; j <= m; j ++)
	ans = max(ans , f[i][j]);
	cout << ans << endl;
}

int main() {
	init();
	dp();
	return 0;
}