# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
211126 | vincent97198 | Arranging Shoes (IOI19_shoes) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#define N 100005
using namespace std;
int BIT[2*N];
inline int lowbit(int x)
{
return x&(-x);
}
void add(int pos,int val)
{
for(;pos<N;pos+=lowbit(pos))
BIT[pos]+=val;
}
int sum(int pos)
{
int ret=0;
for(;pos>0;pos-=lowbit(pos))
ret+=BIT[pos];
return ret;
}
long long count_swap(vector<int> S)
{
map<ll,queue<int>> mp;
long long ans=0;
for(int i=0;i<S.size();++i){
mp[S[i]].push(i);
add(i+1,1);
}
for(int i=0;i<S.size();++i){
mp[S[i]].pop();
int t=mp[-S[i]].front(); mp[-S[i]].pop();
ans+=(sum(i+1)-sum(t-1));
add(t,-1);
}
return ans;
}