CF816B Karen and Coffee

思路：

有点类似于区间修改点查询的树状数组。

实现：

#include <iostream>
#include <cstdio>
using namespace std;

const int MAXN = 200005;
int a[MAXN], n, k, q;

int main()
{
        cin >> n >> k >> q;
        for (int i = 0; i < n; i++)
        {
                int l, r;
                scanf("%d %d", &l, &r);
                a[l]++; a[r + 1]--;
        }
        for (int i = 1; i < MAXN; i++) a[i] += a[i - 1];
        for (int i = 1; i < MAXN; i++)
                if (a[i] >= k) a[i] = 1;
                else a[i] = 0;
        for (int i = 1; i < MAXN; i++) a[i] += a[i - 1];
        for (int i = 0; i < q; i++)
        {
                int l, r;
                scanf("%d %d", &l, &r);
                printf("%d
", a[r] - a[l - 1]);
        }
        return 0;
}