Codeforces 635A Orchestra 【水题】

Codeforces 635A Orchestra 【水题】"/>

Codeforces 635A Orchestra 【水题】

A. Orchestra time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output

Paul is at the orchestra. The string section is arranged in an r × c rectangular grid and is filled with violinists with the exception of n violists. Paul really likes violas, so he would like to take a picture including at least k of them. Paul can take a picture of any axis-parallel rectangle in the orchestra. Count the number of possible pictures that Paul can take.

Two pictures are considered to be different if the coordinates of corresponding rectangles are different.

Input

The first line of input contains four space-separated integers r, c, n, k (1 ≤ r, c, n ≤ 10, 1 ≤ k ≤ n) — the number of rows and columns of the string section, the total number of violas, and the minimum number of violas Paul would like in his photograph, respectively.

The next n lines each contain two integers xi and yi (1 ≤ xi ≤ r, 1 ≤ yi ≤ c): the position of the i-th viola. It is guaranteed that no location appears more than once in the input.

Output

Print a single integer — the number of photographs Paul can take which include at least k violas.

Examples input

2 2 1 1
1 2

output

4

input

3 2 3 3
1 1
3 1
2 2

output

1

input

3 2 3 2
1 1
3 1
2 2

output

4

Note

We will use '*' to denote violinists and '#' to denote violists.

In the first sample, the orchestra looks as follows

*#
**

Paul can take a photograph of just the viola, the  1 × 2 column containing the viola, the  2 × 1 row containing the viola, or the entire string section, for  4 pictures total.

In the second sample, the orchestra looks as follows

#*
*#
#*

Paul must take a photograph of the entire section.

In the third sample, the orchestra looks the same as in the second sample.

合法矩形：里面包含至少k个'#'。

题意：给你一个r*c的格子，里面有n个'#'字符，问有多少个不同的矩形。 矩形的坐标不同即不同。

暴力。

AC代码：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <map>
#include <string>
#define CLR(a, b) memset(a, (b), sizeof(a))
using namespace std;
typedef long long LL;
const int MAXN = 1e3+10;
const int INF = 0x3f3f3f3f;
bool vis[15][15];
bool judge(int x1, int y1, int x2, int y2, int k){int cnt = 0;for(int i = x1; i <= x2; i++) {for(int j = y1; j <= y2; j++) {cnt += vis[i][j];}}return cnt >= k;
}
int main()
{int r, c, n, k; cin >> r >> c >> n >> k;CLR(vis, false); int x, y;for(int i = 0; i < n; i++) cin >> x >> y, vis[x][y] = true;int ans = 0;for(int i = 1; i <= r; i++) for(int j = 1; j <= c; j++)for(int ii = i; ii <= r; ii++) for(int jj = j; jj <= c; jj++)ans += judge(i, j, ii, jj, k);cout << ans << endl;return 0;
}