Submission #424759

#	Time	Username	Problem	Language	Result	Execution time	Memory
424759		amoo_safar	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	80 ms	19060 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 10;

int fen[N];
void Add(int idx){
	for(; idx < N; idx += idx & (-idx))
		fen[idx] ++;
}
int Get(int idx){
	int res = 0;
	for(; idx; idx -= idx & (-idx))
		res += fen[idx];
	return res;
}
vector<int> A[N], B[N];

long long count_swaps(std::vector<int> s) {
	int n = s.size() / 2;
	for(int i = 0; i < n + n; i++)
		(s[i] > 0 ? A : B)[abs(s[i])].push_back(i);
	vector<int> a(n + n, 0);
	for(int i = 0; i <= n; i++)
		for(int j = 0; j < (int) A[i].size(); j++)
			a[A[i][j]] = a[ B[i][j] ] = min(A[i][j], B[i][j]) + 2;
	long long ans = 0;
	for(int i = 0; i <= n; i++)
		for(int j = 0; j < (int) A[i].size(); j++)
			ans += (A[i][j] < B[i][j]);
	for(int i = n + n - 1; i >= 0; i--){
		// cerr << "! " << a[i] << '\n';
		ans += Get(a[i] - 1);
		Add(a[i]);
	}
	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