25求助QwQ

P1908 逆序对

Kawaii_UKE @ 2023-07-30 14:46:27

#include<bits/stdc++.h>
using namespace std;
int a[50010];
int main()
{   
    int n,ans=0;;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            if(a[i]>a[j])
                ans++;
        }
    }
    cout<<ans;
   return 0;
}

by Parrhesiates @ 2023-07-30 15:05:01

超时了吧


by jiangjiangQwQ @ 2023-07-30 15:13:57

这道题要用到归并排序或树状数组。没那么简单滴!


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