Submission #958804

#	Time	Username	Problem	Language	Result	Execution time	Memory
958804		MuntherCarrot	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	47 ms	15036 KiB

shoes

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

using namespace std;

#define ll long long

const int MAXN = 2e5 + 10;
int bit[MAXN];

void upd(int i, int val){
    for(i++; i <= MAXN; i += -i & i){
        bit[i - 1] += val;
    }
}

ll clc(int i){
    ll res = 0;
    for(i++; i > 0; i -= -i & i){
        res += bit[i - 1];
    }
    return res;
}

ll clc(int l, int r){
    return clc(r) - clc(l - 1);
}

long long count_swaps(vector<int> s) {
    ll res = 0;
    int n = s.size();
    vector<vector<int>> vec(n + 1);
    for(int i = n - 1; i >= 0; i--){
        vec[s[i] + n / 2].push_back(i);
    }
    for(int i = 0; i < n; i++){
        if(vec[s[i] + n / 2].back() != i) continue;
        int x = vec[-s[i] + n / 2].back();
        vec[s[i] + n / 2].pop_back();
        vec[-s[i] + n / 2].pop_back();
        res += x - i - (s[i] < 0) - clc(i, x);
        upd(i, 1);
        upd(x, 1);
    }
	return res;
}

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