Submission #867421

#	Time	Username	Problem	Language	Result	Execution time	Memory
867421		lolismek	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	30 ms	15952 KiB

shoes

#include "shoes.h"
#include <queue>
#include <cassert>

#define pii pair <int, int>

using namespace std;

const int NMAX = 1e5 + 10;

namespace AIB{
    int n;
    int aib[NMAX + 1];

    void init(int _n){
        n = _n;
        for(int i = 0; i <= n; i++){
            aib[i] = 0;
        }
    }

    int lsb(int x){
        return x & -x;
    }

    void update(int pos, int val){
        pos += 1;

        for(int i = pos; i <= n; i += lsb(i)){
            aib[i] += val;
        }
    }

    int query(int pos){
        pos += 1;

        int ans = 0;
        for(int i = pos; i >= 1; i -= lsb(i)){
            ans += aib[i];
        }
        return ans;
    }
}

vector <int> pos[NMAX + 1];
int par[NMAX + 1];
bool viz[NMAX + 1];

long long count_swaps(vector<int> s){
    int n = (int)s.size();

    for(int i = 0; i < n; i++){
        pos[(s[i] < 0 ? -s[i] : s[i])].push_back(i);
    }

    for(int col = 1; col <= n; col++){
        queue <pii> St;
        for(int j = 0; j < (int)pos[col].size(); j++){
            int i = pos[col][j];
            if(!St.empty() && St.front().first == -s[i]){
                par[i] = St.front().second;
                par[St.front().second] = i;
                St.pop();
            }else{
                St.push({s[i], i});
            }
        }
    }

    AIB::init(n);
    for(int i = 0; i < n; i++){
        AIB::update(i, +1);
    }

    long long ans = 0;

    for(int i = 0; i < n; i++){
        if(!viz[i]){
            viz[i] = viz[par[i]] = true;
            AIB::update(i, -1);
            AIB::update(par[i], -1);
            ans += AIB::query(par[i]) - AIB::query(i) + (s[i] > s[par[i]]);
        }
    }

    return ans;
}

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