Submission #560283

#	Time	Username	Problem	Language	Result	Execution time	Memory
560283		ngpin04	Arranging Shoes (IOI19_shoes)	C++14	100 / 100	90 ms	20444 KiB

shoes

#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define TASK ""
#define ALL(x) (x).begin(), (x).end() 
using namespace std;
template <typename T1, typename T2> bool mini(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maxi(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}
const int N = 2e5 + 5; 
const int oo = 1e9;
const long long ooo = 1e18;
const int mod = 1e9 + 7; // 998244353;
const long double pi = acos(-1);
#include "shoes.h"

vector <int> pos[2 * N];

int bit[N];
int n;

void update(int pos, int val) {
	pos++;
	for (; pos <= n; pos += pos & -pos)
		bit[pos] += val;
}

int getval(int pos) {
	int res = 0;
	pos++;
	for (; pos; pos -= pos & -pos)
		res += bit[pos];
	return res;
}

long long count_swaps(std::vector<int> s) {
	n = s.size();
	vector <pair <int, int>> p;
	for (int i = n - 1; i >= 0; i--)
		pos[s[i] + n].push_back(i);

	for (int i = 0; i < n; i++) {
		if (!pos[s[i] + n].size() || pos[s[i] + n].back() != i)
			continue;
		p.push_back(mp(pos[-s[i] + n].back(), i));
		pos[-s[i] + n].pop_back();
		pos[s[i] + n].pop_back();
	}

	sort(ALL(p));
	for (int i = 0; i < n; i++) 
		update(i, 1);

	long long ans = 0;
	for (pair <int, int> pir : p) {
		// cerr << pir.fi << " " << pir.se << "\n";
		ans += getval(pir.fi) + getval(pir.se) - 3;
		update(pir.fi, -1);
		update(pir.se, -1);
		ans += (s[pir.fi] < 0);
	}
	return ans;
}

//#include "grader.cpp"

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