我的提交记录 链接 代码如下：

#include <iostream>
#include <cmath>
//#include <cstring>
//#include <cstdio>
#include <algorithm>
#include <vector>
//#include <numeric>

//#define UC unsigned char
//#define US unsigned short
//#define U unsigned int
//#define ULL unsigned long long
//#define DEBUG


struct Point {
	int r, c, value;
};


bool compare(Point a, Point b)
{
	return a.value < b.value;
}


int main()
{
	using namespace std;
	
	int r, c;
	cin >> r >> c;
	vector<Point> points(r * c, Point());
	int** dp = new int*[r];
	points.shrink_to_fit();
	for (int i = 0; i < r; i++)
	{
		dp[i] = new int[c];
		for (int j = 0; j < c; j++)
		{
			dp[i][j] = -1;
			cin >> points[i * c + j].value;
			points[i * c + j].r = i;
			points[i * c + j].c = j;
		}
	}
//	printf("%d %d %d\n", points[5].r, points[5].c, points[5].value);

	sort(points.begin(), points.end(), compare);
//	printf("%d %d %d\n", points[r * c - 1].r, points[r * c - 1].c, points[r * c - 1].value);
//	printf("%d\n", points[0].value);
	int up, down, left, right, cr, cc, cmax = -1;
	for (int i = 0; i < r * c; i++)
	{
		cr = points[i].r;
		cc = points[i].c;
		up = cr > 0 ? dp[cr - 1][cc] : -1;
		down = cr < r - 1 ? dp[cr + 1][cc] : -1;
		left = cc > 0 ? dp[cr][cc - 1] : -1;
		right = cc < c - 1 ? dp[cr][cc + 1] : -1;
		dp[cr][cc] = max(
			0, max(
			up, max(
			down, max(
			left,
			right)))
		) + 1;
		cmax = max(cmax, dp[cr][cc]);
	}
	
	cout << cmax << endl;
	
	return 0;
}