红黑相间，请求支援

#include <bits/stdc++.h>
using namespace std;
int sum[10005][10005],a[10005][10005];
int main()
{
	int n,m,maxx=1e-9;
	scanf("%d %d",&n,&m);
	for (int i=1;i<=n;i++)
	{
		int x,y,v;
		scanf("%d %d %d",&x,&y,&v);
		a[x+1][y+1]+=v;
	}
	for (int i=1;i<=n;i++)
	{
		for (int j=1;j<=n;j++)
		{
			sum[i][j]=sum[i-1][j]+sum[i][j-1]-sum[i-1][j-1]+a[i][j];
		}
	}
	for (int i=n-m+1;i<=n;i++)
	{
		for (int j=n-m+1;j<=n;j++)
		{
			maxx=max(maxx,sum[i][j]-sum[i-1][j]-sum[i][j-1]+sum[i-1][j-1]);
		}
	}
	cout<<maxx;
	return 0;
}