[luogu1908]逆序对（upper_bound）

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<vector>
 4 #include<algorithm>
 5 using namespace std;
 6 int n;
 7 vector<int> shu;
 8 int main(){
 9     scanf("%d",&n);    
10     long long s=0,a;
11     int kk[60000];
12     for(int i=0;i<n;i++){
13         scanf("%d",&kk[i]);//核心代码：
14         s+=shu.end()-upper_bound(shu.begin(),shu.end(),kk[i]);
15         shu.insert(upper_bound(shu.begin(),shu.end(),kk[i]),kk[i]);
16     }
17     printf("%d",s);
18     return 0;
19 }