Submission #386932

#	Time	Username	Problem	Language	Result	Execution time	Memory
386932		danielcm585	Arranging Shoes (IOI19_shoes)	C++14	10 / 100	5 ms	5100 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 2e5;
const int ADD = 1e5;
int n;
int pr[N+2], bit[N+2];
vector<int> ls[N+2];

void update(int x, int v) {
    for (int i = x; i <= n; i += i&-i) bit[i] += v;
}

int query(int x, int y) {
    int ret = 0;
    for (int i = y; i; i -= i&-i) ret += bit[i];
    for (int i = x-1; i; i -= i&-i) ret -= bit[i];
    return ret;
}

ll count_swaps(vector<int> s) {
    n = s.size();
    for (int i = 0; i < n; i++) {
        if (!ls[-s[i]+ADD].empty()) {
            int x = ls[-s[i]+ADD].back();
            ls[-s[i]+ADD].pop_back();
            pr[x] = i;
        }
        else ls[s[i]+ADD].push_back(i);
        update(i+1,+1);
    }
    ll ans = 0;
    for (int i = 0; i < n; i++) {
        if (!pr[i]) continue;
        ans += query(i+2,pr[i]) + (s[i] > 0);
        update(pr[i]+1,-1);
    }
    return ans;
}

/*
3
-2 2 2 -2 -2 2

3
-2 3 4 2 -4 -3
*/

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