Submission #377046

#	Time	Username	Problem	Language	Result	Execution time	Memory
377046		rocks03	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	328 ms	273516 KiB

shoes

//#pragma GCC target("avx2")
//#pragma GCC optimization("O3")
//#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

class FenwickTree{
    public:
    int fensz;
    vector<int> fen;
    FenwickTree(int n){
        fensz = n + 10;
        fen.resize(fensz);
    }
    void add(int i, int k){
        ++i;
        for(; i < fensz; i += (i & -i)) fen[i] += k;
    }
    int get(int i){
        ++i;
        int ans = 0;
        for(; i; i -= (i & -i)) ans += fen[i];
        return ans;
    }
};

long long count_swaps(vector<int> a){
    int N = SZ(a);
    const int MAXS = 2e5+100;
    queue<int> ql[MAXS], qr[MAXS];
    rep(i, 0, N){
        if(a[i] < 0) ql[-a[i]].push(i);
        else qr[a[i]].push(i);
    }
    FenwickTree fen(N);
    vector<bool> used(N, false);
    ll ans = 0;
    rep(i, 0, N){
        if(used[i]) continue;
        used[i] = true;
        if(a[i] < 0){
            a[i] *= -1;
            ql[a[i]].pop();
            assert(!qr[a[i]].empty());
            int p = qr[a[i]].front();
            qr[a[i]].pop();
            ans += ((p + fen.get(p)) - (i + fen.get(i))) - 1;
            used[p] = true;
            fen.add(p + 1, -1);
        } else{
            qr[a[i]].pop();
            assert(!ql[a[i]].empty());
            int p = ql[a[i]].front();
            ql[a[i]].pop();
            ans += ((p + fen.get(p)) - (i + fen.get(i)));
            used[p] = true;
            fen.add(p + 1, -1);
        }
    }
    return ans;
}

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