Submission #453732

#	Time	Username	Problem	Language	Result	Execution time	Memory
453732		ponytail	Arranging Shoes (IOI19_shoes)	C++17	15 / 100	169 ms	136916 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 5;
typedef long long ll;
int n;
int inv(int x){
    if(x<0) return -x;
    else if(x>n) return x - n;
    else return x + n;
}
ll count_swaps(vector<int> S){
    ll ans1 = 0, ans2 = 0;
    n = S.size() / 2;
    queue<int> mp[2 * n + 2];
    int nxt = 0;
    for(int i=0; i<2*n; i++) {
        if(mp[inv(S[i])].size()){
            ans1 += abs(mp[inv(S[i])].front() - nxt) + abs(i - nxt - 1);
            ans2 += (S[i]<0);
            nxt += 2;
            mp[inv(S[i])].pop();
        }
        else{
            mp[inv(inv(S[i]))].push(i);
        }
    }
    for(int i=1; i<=2*n; i++){
        while(mp[i].size()){
          mp[i].pop();
        }
    }
    ll ans3 = 0, ans4 = 0; nxt = 0;
    reverse(S.begin(), S.end());
    for(int i=0; i<2*n; i++) {
        if(mp[inv(S[i])].size()){
            ans3 += abs(mp[inv(S[i])].front() - nxt) + abs(i - nxt - 1);
            ans4 += (S[i]<0);
            nxt += 2;
            mp[inv(S[i])].pop();
        }
        else{
            mp[inv(inv(S[i]))].push(i);
        }
    }
    return min(ans1 / 2 + ans2, ans3 / 2 + ans4);
}

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