#419（div2) B. Karen and Coffee

题意：给出n个温度区间，k，Q个询问，每个询问给出一个温度区间x--y。问这之间有多少个温度在给出K的温度区间内。

思路：前缀和小技巧

#include<bits/stdc++.h>
using namespace std;
const int N = 3e5+10;

int n,k,q,x,y,a[N],b[N];

int main() {
    scanf("%d%d%d",&n,&k,&q);
    for(int i = 1; i <= n; ++i) {
        scanf("%d%d",&x,&y);
        b[x] += 1;
        b[y+1] += -1;
    }
    for(int i = 1; i <= 200000; ++i) {
        b[i] += b[i-1];
        if(b[i] >= k) {
            a[i] = 1;
        }
        else {
            a[i] = 0;
        }
    }
    for(int i = 1; i <= 200000; ++i) a[i] += a[i-1];
    for(int i=1;i<=q;i++) {
        int x,y;
        scanf("%d%d",&x,&y);
        cout<<a[y] - a[x-1]<<endl;
    }
    return 0;
}