CSP 202104_2

CSP202104_2

目录

• CSP202104_2
  • 题目
  • 思路
  • Code

题目

邻域均值

思路

CSP一贯风格，纯暴力一眼可见的70pts

二维前缀和，没什么要说的

Code

#include<bits/stdc++.h>

using namespace std;

int n;
int l, r, t;
int pre[610][610];
int ans;

int main()
{
	cin >> n >> l >> r >> t;
	for(int i = 1; i <= n; i++)
	{
		for(int j = 1; j <= n; j++)
		{
			int val;
			cin >> val;
			pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + val;
		}
	}
	for(int i = 1; i <= n; i++)
	{
		for(int j = 1; j <= n; j++)
		{
			int x1 = (i - r >= 1 ? i - r : 1);
			int x2 = (i + r <= n ? i + r : n);
			int y1 = (j - r >= 1 ? j - r : 1);
			int y2 = (j + r <= n ? j + r : n);
			int sum = pre[x2][y2] - pre[x1 - 1][y2] - pre[x2][y1 - 1] + pre[x1 - 1][y1 - 1];
			int cnt = (x2 - x1 + 1)*(y2 - y1 + 1);
			if((double)sum / cnt <= (double)t) ans++;
		}
	}
	cout << ans;
	return 0;
}