Submission #1153234

#	Time	Username	Problem	Language	Result	Execution time	Memory
1153234		browntoad	Arranging Shoes (IOI19_shoes)	C++20	50 / 100	87 ms	30792 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"
using namespace std;
#define ll long long
// #define int ll
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) for (int i = (n)-1; i >= 0; i--)
#define RREP1(i, n) for (int i = (n); i >= 1; i--)
#define REP1(i, n) FOR(i, 1, n+1)
#define pii pair<int, int>
#define ppi pair<pii, int>
#define pip pair<int, pii>
#define f first
#define s second
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)((x).size())
#define endl '\n'
#define IOS() ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)

const ll maxn = 1e5+5;
const ll inf = 1e9;
const ll mod = 998244353;

ll pw(ll x, ll p, ll m){
    ll ret = 1;
    while(p > 0){
        if (p & 1){
            ret *= x;
            ret %= m;
        }
        x *= x;
        x %= m;
        p >>= 1;
    }
    return ret;
}
ll inv(ll x, ll m){
    return pw(x, m-2, m);
}

ll bit[2*maxn];
ll query(int a){
    a++;
    ll ret = 0;
    while(a > 0){
        ret += bit[a];
        a -= (a&-a);
    }
    return ret;
}
void modify(int a, ll v){
    a++;
    while(a < maxn){
        bit[a] += v;
        a += (a&-a);
    }
}

ll count_swaps(vector<int> vc){
    int n = SZ(vc);
    REP(i, n) modify(i, 1);

    set<int> qup[n+1], qun[n+1];
    REP(i, n){
        if (vc[i] > 0){
            qup[vc[i]].insert(i);
        }
        else{
            qun[-vc[i]].insert(i);
        }
    }

    ll ans = 0;
    REP(i, n){
        ll pos = 0, cnt;
        if (vc[i] > 0){
            if (qup[vc[i]].find(i) == qup[vc[i]].end()) continue;

            pos = (*qun[vc[i]].begin());
            cnt = query(pos)-1;

            ans += cnt;
            qun[vc[i]].erase(pos);
            modify(pos, -1);
            qup[vc[i]].erase(i);
            modify(i, -1);
        }
        else{
            if (qun[-vc[i]].find(i) == qun[-vc[i]].end()) continue;

            pos = (*qup[-vc[i]].begin());
            cnt = query(pos)-1;

            ans += cnt-1;
            qup[-vc[i]].erase(pos);
            modify(pos, -1);
            qun[-vc[i]].erase(i);
            modify(i, -1);
        }

    }
    return ans;
}

/*
signed main(){
    cout<<count_swaps({-1, 1})<<endl;
    //cout<<count_swaps({1, 2, -1, 2, 1, -2, -2, -1})<<endl;
}
*/


/*
4 4
1 2
2 3
3 1
1 4
*/

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 15