Submission #1187090

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187090		eri16	Arranging Shoes (IOI19_shoes)	C++20	10 / 100	0 ms	328 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>
#include <vector>
#include <algorithm>

long long count_swaps(std::vector<int> s) {
    long long swaps = 0;
    int n = s.size();

    for (int i = 0; i < n; ++i) {
        // only try to pair a left shoe (positive) that isn't already
        // immediately preceded by its right mate:
        if (s[i] > 0 && !(i > 0 && s[i-1] == -s[i])) {
            // find its matching right shoe
            int j = i+1;
            while (j < n && s[j] != -s[i]) ++j;

            // move that right shoe from j to i, one adjacent swap at a time
            while (j > i) {
                std::swap(s[j], s[j-1]);
                --j;
                ++swaps;
            }
            // now s[i] is the right shoe, s[i+1] is the left shoe
        }
    }

    return swaps;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15