Submission #253502

#	Time	Username	Problem	Language	Result	Execution time	Memory
253502		Erkhemkhuu	Arranging Shoes (IOI19_shoes)	C++17	85 / 100	94 ms	6776 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
const ll N = 5005;
ll count_swaps(vector <int> vc) {
    ll n, i, res, cur, j, k;
    n = vc.size();
    set <ll> cnt;
    for(auto &x: vc)
        cnt.insert(abs(x));
    res = 0;
    if(cnt.size() == 1) {
        vector <ll> left;
        for(i = 0; i < n; i++)
            if(vc[i] < 0) left.pb(i);
        for(i = 0; i < n / 2; i++)
            res += (abs(left[i] - (i + i)));
        return res;
    }
    if(n <= N) {
        for(i = 0; i < n; i += 2) {
            for(j = i + 1; j < n; j++) {
                if(-vc[i] == vc[j]) {
                    for(k = j; k >= i + 2; k--) {
                        swap(vc[k], vc[k - 1]);
                        res++;
                    }
                    break;
                }
            }
            res += (!(abs(vc[i]) == abs(vc[i + 1]) && vc[i] < vc[i + 1]));
        }
        return res;
    }
    res = 1ll * (n / 2) * ((n / 2) - 1) / 2;
    return res;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:10:19: warning: unused variable 'cur' [-Wunused-variable]
     ll n, i, res, cur, j, k;
                   ^~~

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