Submission #230973

#	Time	Username	Problem	Language	Result	Execution time	Memory
230973		vioalbert	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	341 ms	146236 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int N = 2e5+5;
int n;
ll ft[N];
unordered_map<int, queue<int>> q;

void update(int x, ll val) {
	for(; x <= n+5; x+=x&(-x)) ft[x]+=val;
}

ll query(int x) {
	ll ret = 0;
	for(; x > 0; x-=x&(-x)) ret+=ft[x];
	return ret;
}

ll count_swaps(vector<int> a) {
	n = a.size();
	memset(ft, 0, sizeof ft);
	ll ans = 0;

	for(int i = 0; i < n; i++) {
		bool right = a[i] > 0;
		if(i > 0 && !q[-a[i]].empty()) {
			int x = q[-a[i]].front(); q[-a[i]].pop();
			ans += query(i+1)-query(x+1);
			if(!right) ans++;
			update(x+1, 1);
			update(i+2, -1);
		} else {
			q[a[i]].push(i);
		}

		update(i+1, 1);
	}

	q.clear();

	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