Submission #1036875

#	Time	Username	Problem	Language	Result	Execution time	Memory
1036875		DeathIsAwe	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	166 ms	279896 KiB

shoes

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

int segment[262144];

void update(int a, int b) {
	a += 131072; b += 131072;
	while (a <= b) {
		if (a % 2 == 1) {segment[a++]++;}
		if (b % 2 == 0) {segment[b--]++;}
		a /= 2; b /= 2;
	}
}

int give(int a) {
	int total = a;
	a += 131072; 
	while (a > 0) {
		total += segment[a];
		a /= 2;
	}
	return total;
}

long long count_swaps(vector<int> s) {
	for (int i=0;i<262144;i++) {
		segment[i] = 0;
	}
	int n = s.size(), shift = *max_element(s.begin(), s.end()), ans = 0;
	vector<deque<int>> positions(2 * shift + 1);
	for (int i=0;i<n;i++) {
		if (positions[shift - s[i]].empty()) {
			positions[shift + s[i]].push_back(i);
		} else {
			ans += i - give(positions[shift - s[i]][0]);
			update(positions[shift - s[i]][0], i);
			if (s[i] > 0) {
				ans--;
			}
			positions[shift - s[i]].pop_front();
		}
	}
	return ans;
}

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