Submission #992021

#	Time	Username	Problem	Language	Result	Execution time	Memory
992021		coolboy19521	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	446 ms	146924 KiB

shoes

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

using namespace std;

const int sz = 2e5 + 10;

int st[sz];
int n;

int query(int x) {
	int sm = 0;
	for (; 0 < x; x -= x & -x) sm += st[x];

	return sm;
}

void update(int x) {
	for (; x <= n; x += x & -x) {
		st[x] ++;
	}
}

long long count_swaps(std::vector<int> s) {
	map<int,queue<int>>cl;
	n = s.size();

	for (int i = 0; i < n; i ++) {
		cl[s[i]].push(i);
	}

	long long r = 0;

	for (int i = 0; i < n; i ++) {
		auto it = query(i + 1) - query(i);
		if (it != 0) continue;

		int ix = cl[-s[i]].front();
		int vs = i - query(i + 1);
		int ve = ix - query(ix + 1);

		r += (ve - vs);

		if (s[i] < 0) {
			r --;
		}

		cl[-s[i]].pop();
		cl[s[i]].pop();

		update(i + 1);
		update(ix + 1);
	}

	return r;
}

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