Submission #769680

#	Time	Username	Problem	Language	Result	Execution time	Memory
769680		SanguineChameleon	Arranging Shoes (IOI19_shoes)	C++17	50 / 100	1084 ms	16484 KiB

shoes

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

const int maxN = 1e5 + 20;
int order[maxN * 2];
int sizes[maxN * 2];
int match[maxN * 2];
bool flag[maxN * 2];
vector<int> shoes[maxN][2];

long long count_swaps(vector<int> _sizes) {
	int n = (int)_sizes.size() / 2;
	for (int i = 1; i <= n * 2; i++) {
		sizes[i] = _sizes[i - 1];
		if (sizes[i] < 0) {
			shoes[-sizes[i]][0].push_back(i);
		}
		else {
			shoes[sizes[i]][1].push_back(i);
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j < (int)shoes[i][0].size(); j++) {
			match[shoes[i][0][j]] = shoes[i][1][j];
			match[shoes[i][1][j]] = shoes[i][0][j];
		}
	}
	int cnt = 0;
	for (int i = 1; i <= n * 2; i++) {
		if (!flag[i]) {
			order[i] = cnt + (sizes[i] < 0 ? 1 : 2);
			order[match[i]] = cnt + (sizes[match[i]] < 0 ? 1 : 2);
			flag[i] = true;
			flag[match[i]] = true;
			cnt += 2;
		}
	}
	int res = 0;
	for (int i = 1; i <= n * 2; i++) {
		for (int j = i + 1; j <= n * 2; j++) {
			if (order[i] > order[j]) {
				res++;
			}
		}
	}
	return res;
}

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