# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
530810 | SavicS | Arranging Shoes (IOI19_shoes) | C++17 | 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 <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pdd;
#define ff(i,a,b) for(int i = a; i <= b; i++)
#define fb(i,b,a) for(int i = b; i >= a; i--)
#define trav(a,x) for (auto& a : x)
#define sz(a) (int)(a).size()
#define pb push_back
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
const int mod = 1000000007;
const int inf = 1e9 + 5;
const int mxN = 100005;
int n;
int niz[mxN];
set<int> A[mxN];
set<int> B[mxN];
int dud[mxN];
void upd(int x, int val){
while(x <= mxN){
dud[x] += val;
x += x&(-x);
}
}
int query(int x){
int sum = 0;
while(x > 0){
sum += dud[x];
x -= x&(-x);
}
return sum;
}
ll count_swaps(vector<int> S){
n = sz(S); ff(i,1,n)niz[i] = S[i - 1];
ff(i,1,n){
if(niz[i] > 0)A[niz[i]].insert(i);
if(niz[i] < 0)B[-niz[i]].insert(i);
}
ff(i,0,mxN - 1)dud[i] = 0;
ll rez = 0;
ff(i,1,n){
int X = niz[i];
if(X > 0){
if(A[X].count(i) == 0)continue;
A[X].erase(i);
auto pos = B[X].begin(); B[X].erase(pos);
rez += *pos - i - (query(*pos) - query(i - 1));
upd(*pos, 1);
}
else{
if(B[-X].count(i) == 0)continue;
B[-X].erase(i);
auto pos = A[-X].begin(); A[-X].erase(pos);
rez += *pos - i - 1 - (query(*pos) - query(i - 1));
upd(*pos, 1);
}
}
return rez;
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
vector<int> A(n);
ff(i,0,n - 1)cin >> A[i];
cout << count_swaps(A) << '\n';
return 0;
}
/*
// probati bojenje sahovski
*/