mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
118 lines
2.4 KiB
C++
118 lines
2.4 KiB
C++
#include <set>
|
||
#include <map>
|
||
#include <list>
|
||
#include <cmath>
|
||
#include <ctime>
|
||
#include <deque>
|
||
#include <queue>
|
||
#include <stack>
|
||
#include <cstdio>
|
||
#include <string>
|
||
#include <vector>
|
||
#include <cctype>
|
||
#include <cstring>
|
||
#include <sstream>
|
||
#include <fstream>
|
||
#include <cstdlib>
|
||
#include <cassert>
|
||
#include <iostream>
|
||
#include <algorithm>
|
||
|
||
using namespace std;
|
||
//Constant Declaration
|
||
/*--------------------------*/
|
||
//#define LL long long
|
||
#define LL __int64
|
||
const int M=100001;
|
||
const int INF=1<<30;
|
||
const double EPS = 1e-11;
|
||
const double PI = acos(-1.0);
|
||
/*--------------------------*/
|
||
// some essential funtion
|
||
/*----------------------------------*/
|
||
void Swap(int &a,int &b){ int t=a;a=b;b=t; }
|
||
int Max(int a,int b){ return a>b?a:b; }
|
||
int Min(int a,int b){ return a<b?a:b; }
|
||
int Gcd(int a,int b){ while(b){b ^= a ^=b ^= a %= b;} return a; }
|
||
/*----------------------------------*/
|
||
//for (i = 0; i < n; i++)
|
||
/*----------------------------------*/
|
||
|
||
LL c[M];
|
||
int a[M];
|
||
int left_lower[M], right_lower[M];//分别是，在第i个数左右边，比第i个数小的个数
|
||
int n = 100000;
|
||
|
||
|
||
int LowBit(int x)
|
||
{
|
||
return x&(-x);
|
||
}
|
||
|
||
int Sum(int k)
|
||
{
|
||
int sum = 0;
|
||
while (k > 0)
|
||
{
|
||
sum += c[k];
|
||
k -= LowBit(k);
|
||
}
|
||
return sum;
|
||
}
|
||
|
||
void Update(int k, int sc)
|
||
{
|
||
while (k <= 100000)
|
||
{
|
||
c[k] += sc;
|
||
k += LowBit(k);
|
||
}
|
||
}
|
||
|
||
|
||
|
||
int main()
|
||
{
|
||
//freopen("in.txt","r",stdin);
|
||
//freopen("out.txt","w",stdout);
|
||
int t, case1 = 0;
|
||
scanf("%d", &t);
|
||
int m;
|
||
int i, j;
|
||
int num;
|
||
//scanf("%d%d", &n, &m);
|
||
while (t--)
|
||
{
|
||
scanf("%d", &num);
|
||
memset(c, 0, sizeof(c));
|
||
memset(left_lower, 0, sizeof(left_lower));
|
||
memset(right_lower, 0, sizeof(right_lower));
|
||
for (i = 1; i <= num; i++)
|
||
{
|
||
scanf("%d", &a[i]);
|
||
left_lower[i] += Sum(a[i] - 1);///Sum(a[i] - 1)：插入该数前，区间1到a[i]-1的总个数
|
||
Update(a[i], 1);
|
||
}
|
||
|
||
memset(c, 0, sizeof(c));
|
||
for (i = num; i > 0; i--)//顺序插入
|
||
{
|
||
right_lower[i] += Sum(a[i] - 1);
|
||
Update(a[i], 1);
|
||
}
|
||
|
||
LL ans = 0;
|
||
|
||
for (i = 1; i <= num; i++)//逆序插入
|
||
{
|
||
ans += left_lower[i]*(num - i - right_lower[i]);//由于只能求比其小的个数，可以用i右边的总个数见减比他小的来求比他大的个数。
|
||
ans += (i - 1 - left_lower[i])*right_lower[i];//
|
||
}
|
||
|
||
printf("%I64d\n", ans);
|
||
}
|
||
|
||
|
||
return 0;
|
||
}
|