题解 | #求逆序数#

import java.util.Scanner;

public class NC208813 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int []array = new int[n];
        for(int i=0;i<n;i++){
            array[i] = sc.nextInt();
        }
        int count = 0;
        for(int i = 0;i<n;i++){
            for(int j = i;j<n;j++){
                if(array[i]>array[j]) count++;
            }
        }
        System.out.println(count);
    }
}