第十三届蓝桥杯C++C组省赛H题，Python A 组省赛 F 题，Ptyhon C 组省赛 H 题—— 重新排序

import java.io.*;
import java.util.Arrays;


public class Main {
    static int N=100010;
    static int[] a=new int[N];
    static long[] s=new long[N];
    //差分数组
    static long[] g=new long[N];
    static int n;
    static BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    public static void main(String[] args) throws IOException {
        n=Integer.parseInt(br.readLine());
        String[] v=br.readLine().split(" ");
        for (int i = 1; i <=n; i++) {
            a[i]=Integer.parseInt(v[i-1]);
            s[i]=s[i-1]+a[i];
        }
        int m=Integer.parseInt(br.readLine());
        long res=0;
        for (int i = 0; i < m; i++) {
            v=br.readLine().split(" ");
            int l=Integer.parseInt(v[0]);
            int r=Integer.parseInt(v[1]);
            g[l]++;
            g[r+1]--;
            res+=s[r]-s[l-1];
        }
        for (int i = 1; i <=n; i++) {
            g[i]+=g[i-1];
        }
        long ans=0;
        Arrays.sort(a);
        Arrays.sort(g);
        int pre=g.length-1;
        while (g[pre]!=0){
            ans+=g[pre] *a[pre];
            pre--;
        }
        System.out.println(ans-res);
    }
}