# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1272965 | arkanefury | Arranging Shoes (IOI19_shoes) | C++20 | 0 ms | 0 KiB |
#include "shoes.h"
#include <bits/stdc++.h>
#define sz size()
#define all(v) v.begin(), v.end()
#define pb push_back
using namespace std;
const int N = 2e5+5;
int a[N], b[N], t[N*6], n;
vector<int>g[N];
void upd(int pos, int v = 1, int tl = 1, int tr = n){
if(tl == tr){
t[v] = 1;
return;
}
int tm = (tl + tr) >> 1;
if(pos <= tm)upd(pos, v*2, tl, tm);
else upd(pos, v*2+1, tm+1, tr);
t[v] = t[v*2] + t[v*2+1];
}
int get(int l, int r, int v = 1, int tl = 1, int tr = n){
if(l <= tl && tr <= r)return t[v];
if(l > tr || tl > r)return 0;
int tm = (tl + tr) >> 1;
return get(l, r, v*2, tl, tm) + get(l, r, v*2+1, tm+1, tr);
}
long long count_swaps(vector <int> v){
n = v.sz, k;
long long ans = 0;
for(int i = 0; i < n; i ++){
if(v[i] < 0)g[abs(v[i]) + n].pb(i);
else g[v[i]].pb(i);
}
for(int i = 1; i <= 2*n; i ++)reverse(all(g[i]));
for(int i = 0; i < n; i ++){
if(b[i])continue;
if(v[i] < 0){
int x = abs(v[i]);
x = g[x][g[x].sz-1];
k = get(i, x);
ans += x - i - 1 - k;
upd(x);
g[abs(v[i])].pop_back();
}
else{
int x = v[i] + n;
k = get(i, g[x][g[x].sz-1]);
ans += g[x][g[x].sz-1] - i - k;
upd(g[x][g[x].sz-1]);
g[x].pop_back();
}
}
return ans;
}