Submission #742684

#	Time	Username	Problem	Language	Result	Execution time	Memory
742684		Andrei_ierdnA	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	371 ms	148432 KiB

shoes

#include "shoes.h"
#include <queue>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define ordered_set(x) tree<x, null_type, less<x>, rb_tree_tag, tree_order_statistics_node_update>

long long count_swaps(std::vector<int> s) {
	long long i = 0, j = 0, aux = 0, ans = 0, dist = 0, n = s.size() / 2;
	bool viz[200100];
	queue<int> lpoz[100100], rpoz[100100];
	ordered_set(int) sset;
	for (i = 0; i < 2*n; i++) {
        if (s[i] < 0) {
            lpoz[-s[i]].push(i);
        }
        else {
            rpoz[s[i]].push(i);
        }
        sset.insert(i);
        viz[i] = false;
	}
	for (i = 0; i < 2*n; i++) {
        if (!viz[i]) {
            if (s[i] < 0) {
                lpoz[-s[i]].pop();
                j = rpoz[-s[i]].front();
                rpoz[-s[i]].pop();
                aux = 0;
            }
            else {
                rpoz[s[i]].pop();
                j = lpoz[s[i]].front();
                lpoz[s[i]].pop();
                aux = 1;
            }
            viz[i] = viz[j] = true;
            dist = sset.order_of_key(j) - sset.order_of_key(i) - 1 + aux;
            ans += dist;
            sset.erase(i);
            sset.erase(j);
        }
	}
	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