Submission #1030708

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030708		Zicrus	Arranging Shoes (IOI19_shoes)	C++17	10 / 100	0 ms	348 KiB

shoes

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

typedef long long ll;

ll count_swaps(vector<int> a) {
    ll n = a.size() / 2;
    vector<vector<ll>> seenQNeg(n+10);
    vector<vector<ll>> seenQPos(n+10);
    ll res = 0;
    for (int i = 0; i < a.size(); i++) {
        auto &q = a[i] < 0 ? seenQNeg[-a[i]] : seenQPos[a[i]];
        auto &pairQ = a[i] > 0 ? seenQNeg[a[i]] : seenQPos[-a[i]];
        if (pairQ.empty()) {
            (a[i] < 0 ? seenQNeg[abs(a[i])] : seenQPos[abs(a[i])]).push_back(i);
        }
        else {
            ll id = pairQ.back();
            pairQ.pop_back();
            if (a[i] < 0) {
                res += abs(id - i);
            }
            else {
                res += abs(id - i) - 1;
            }
        }
    }
    return res;
}

Compilation message (stderr)

shoes.cpp: In function 'll count_swaps(std::vector<int>)':
shoes.cpp:12:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for (int i = 0; i < a.size(); i++) {
      |                     ~~^~~~~~~~~~
shoes.cpp:13:15: warning: unused variable 'q' [-Wunused-variable]
   13 |         auto &q = a[i] < 0 ? seenQNeg[-a[i]] : seenQPos[a[i]];
      |               ^

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