Submission #976792

#	Time	Username	Problem	Language	Result	Execution time	Memory
976792		efedmrlr	Arranging Shoes (IOI19_shoes)	C++17	50 / 100	1097 ms	26672 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"

#define lli long long int
#define ld long double
#define pb push_back
#define MP make_pair
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define REP(i, n) for(int i = 0; (i) < (n); (i)++)

using namespace std;

void fastio() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
}

const int N = 1e5 + 5;
const int INF = 1e9 + 500;

long long count_swaps(std::vector<int> s) {
    int n = (int)s.size() / 2;

    map<int, vector<int> > occ;
    for(int i = 0; i < 2*n; i++) {
        occ[s[i]].pb(i);
    }
    vector<array<int, 2> > pr;

    for(int i = 1; i <= n; i++) {
        auto &x = occ[i];
        auto &y = occ[-i];

        for(int j = 0; j < x.size(); j++) {
            pr.pb({y[j], x[j]});
        }
    }
    vector<int> ord(2 * n, 0);
    sort(all(pr), [](array<int, 2> &x, array<int, 2> &y) {
        return x[0] + x[1] < y[0] + y[1];
    });
    
    for(int i = 0; i < n; i++) {
        ord[pr[i][0]] = i * 2;
        ord[pr[i][1]] = i * 2 + 1;
    }
    lli inv = 0;
    for(int i = 0; i < 2 * n; i++) {
        for(int j = i + 1; j < 2 * n; j++) {
            if(ord[i] > ord[j]) {
                inv++;
            }
        } 
    }

    return inv;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:35:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |         for(int j = 0; j < x.size(); j++) {
      |                        ~~^~~~~~~~~~

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