Submission #589776

#	Time	Username	Problem	Language	Result	Execution time	Memory
589776		shrimb	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	389 ms	285348 KiB

shoes

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

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class x>
using ordered_set = tree<x, null_type,less<x>, rb_tree_tag,tree_order_statistics_node_update>;

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

	int a[n];
	int b[n];
	int c[n];
	int d[n];

	memset(d, 0, sizeof d);

	queue<int> p[n + 1];
	stack<int> p2[n + 1];

	for (int i = 0 ; i < n ; i++) {
		if (s[i] > 0) p[s[i]].push(i);
		else p2[-s[i]].push(i);
	}
	int cnt = 0, cnt2 = 0;
	for (int i = 0 ; i < n ; i++) {
		if (s[i] < 0) {
			c[cnt] = i;
			a[i] = cnt++;
			c[cnt] = p[-s[i]].front();
			a[p[-s[i]].front()] = cnt++;
			p[-s[i]].pop();
		}
	}
	cnt = 0;
	for (int i = 0 ; i < n ; i++) {
		if (d[i]) continue;
		if (a[i] & 1) {
			b[i] = cnt + 1;
			b[c[a[i] - 1]] = cnt;
			cnt += 2;
		} else {
			b[i] = cnt;
			b[c[a[i] + 1]] = cnt + 1;
			cnt += 2;
		}
	}

	long long ret = 0;
	ordered_set<int> os;

	for (int i = n - 1 ; i >= 0 ; i--) {
		ret += os.order_of_key(b[i]);
		os.insert(b[i]);
	}
	return ret;

}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:29:15: warning: unused variable 'cnt2' [-Wunused-variable]
   29 |  int cnt = 0, cnt2 = 0;
      |               ^~~~

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