| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 811021 | Essa2006 | 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>
//#include "shoes.h"
#include <cstdio>
#include <cassert>
using namespace std;
#define ll long long
#define endl '\n'
#define FF firtst
#define SS second
#define all(a) a.begin(), a.end()
#define mod (ll)(1000000007)
const int pr=20, s_p=(1<<pr), e_p=(1<<(pr+1))-1;
vector<int>S;
map<int, queue<int>>mp;
void pre(){
S.clear(), mp.clear();
S.resize(1<<(pr+1));
}
void update(int id, int u, int v, int l, int r){
if(l>v || r<u)
return;
if(l>=u && r<=v){
S[id]++;
return;
}
int md=(l+r)/2;
update(id*2, u, v, l, md);
update(id*2+1, u, v, md+1, r);
}
int get(int ind){
ll res=S[ind];
while(ind/=2)
res+=S[ind];
return res;
}
ll count_swaps(vector<int> A){
int n=A.size();
pre();
ll ans=0;
for(int i=0;i<n;i++){
if(A[i]>0 && !mp[-A[i]].empty()){
int u=mp[-A[i]].front();
mp[-A[i]].pop();
u+=get(u+s_p);
ans+=i-u-1;
if(u!=i-1)
update(1, u+1+s_p, i-1+s_p, s_p, e_p);
}
else if(A[i]<0 && !mp[-A[i]].empty()){
int u=mp[-A[i]].front();
mp[-A[i]].pop();
u+=get(u+s_p);
ans+=i-u;
update(1, u+s_p, i-1+s_p, s_p, e_p);
}
else{
mp[A[i]].push(i);
}
}
return ans;
}
int main() {
int n;
assert(1 == scanf("%d", &n));
vector<int> S(2 * n);
for (int i = 0; i < 2 * n; i++)
assert(1 == scanf("%d", &S[i]));
fclose(stdin);
long long result = count_swaps(S);
printf("%lld\n", result);
fclose(stdout);
return 0;
}