Submission #219769

#	Time	Username	Problem	Language	Result	Execution time	Memory
219769		VEGAnn	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	107 ms	15096 KiB

shoes

#include <bits/stdc++.h>
#include "shoes.h"
#define all(x) x.begin(),x.end()
#define PB push_back
#define sz(x) ((int)x.size())
using namespace std;
typedef long long ll;
const int N = 200100;
vector<int> vc[N];
ll ans = 0;
int fen[N];
bool mrk[N];

int sum(int x){
    int res = 0;
    for (; x >= 0; x = (x & (x + 1)) - 1)
        res += fen[x];
    return res;
}

void upd(int x, int vl){
    for (; x < N; x = (x | (x + 1)))
        fen[x] += vl;
}

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

    for (int i = sz(s) - 1; i >= 0; i--)
        vc[s[i] + n].PB(i);

    for (int i = 0; i < sz(s); i++){
        if (mrk[i]) continue;

        if (s[i] > 0)
            ans++;

        vc[s[i] + n].pop_back();

        int real_i = i + sum(i);

        int j = vc[-s[i] + n].back();

        vc[-s[i] + n].pop_back();
        mrk[j] = 1;

        int real_j = sum(j) + j;

        ans += real_j - real_i - 1;

        upd(i, 1);
        upd(j, -1);
    }

    return ans;
}

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