Submission #286297

#	Time	Username	Problem	Language	Result	Execution time	Memory
286297		BeanZ	Arranging Shoes (IOI19_shoes)	C++14	85 / 100	57 ms	8572 KiB

shoes

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

using namespace std;

#define ll long long
#define endl '\n'

const int N = 2e5 + 5;
vector<ll> node[100005];
ll a[200005], in[200005];
ll count_swaps(vector<int> s){
        ll ans = 0;
        int n = s.size();
        if (n <= 2000){
                for (int i = 0; i < n; i++){
                        bool flag = false;
                        for (int j = 0; j < i; j++){
                                if (((s[j] + s[i]) == 0) && in[j] == 0){
                                        flag = true;
                                        if (s[i] < 0) {
                                                ans = ans + i - j;
                                                for (int k = i - 1; k >= j; k--){
                                                        swap(s[k], s[k + 1]);
                                                        swap(in[k], in[k + 1]);
                                                }
                                                in[j + 1] = 1;
                                                in[j] = 1;
                                                break;
                                        } else {
                                                ans = ans + i - j - 1;
                                                for (int k = i - 1; k > j; k--){
                                                        swap(s[k], s[k + 1]);
                                                        swap(in[k], in[k + 1]);
                                                }
                                                in[j + 1] = 1;
                                                in[j] = 1;
                                                break;
                                        }
                                }
                        }
                }
                return ans;
        } else {
                ll cnt = 1;
                for (int i = 0; i < n; i++){
                        if (s[i] > 0){
                                node[s[i]].push_back(cnt - 1);
                                cnt += 2;
                        }
                }
                for (int i = 1; i <= (n / 2); i++){
                        if (node[i].size() == 0) continue;
                        reverse(node[i].begin(), node[i].end());
                }
                for (int i = 0; i < n; i++){
                        if (s[i] < 0){
                                ans = ans + abs(i - node[-s[i]].back());
                                node[-s[i]].pop_back();
                        }
                }
                return ans;
        }
}
/*
int main(){
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        if (fopen("VietCT.INP", "r")){
                freopen("VietCT.INP", "r", stdin);
                freopen("VietCT.OUT", "w", stdout);
        }
        ll n;
        cin >> n;
        vector<int> mem;
        for (int i = 1; i <= (2 * n); i++){
                ll u;
                cin >> u;
                mem.push_back(u);
        }
        cout << count_swaps(mem);
}
*/
/*
2
-2 -2 2 2
*/

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:17:30: warning: variable 'flag' set but not used [-Wunused-but-set-variable]
   17 |                         bool flag = false;
      |                              ^~~~

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