Submission #1014343

#	Time	Username	Problem	Language	Result	Execution time	Memory
1014343		KasymK	Arranging Shoes (IOI19_shoes)	C++17	Compilation error	0 ms	0 KiB

shoes

#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define ff first
#define ss second
#define all(v) v.begin(), v.end()

ll count_swaps(vector<int> v){
    int n = (int)v.size(), ok = 1;
    n >>= 1;
    for(int i = 0; i < n; ++i)
        ok &= (v[i] < 0);
    for(int i = 0; i < n; ++i)
        ok &= (-v[i] == v[i+n]);
    ll ans = 0;
    if(ok){
        n--;
        ans = n*1ll*(n+1)/2;
        return ans;
    }
    n <<= 1;
    for(int i = 0; i < n-1; i+=2){
        if(-v[i] == v[i+1]){
            // it means these two shoes are the same
            if(v[i] > 0)
                swap(v[i], v[i+1]), ans++;
        }
        int ad;
        for(int j = i+1; j < n; ++j)
            if(-v[i] == v[j]){
                ad = j;
                break;
            }
        for(int j = ad; j > i+1; --j)
            swap(v[j], v[j-1]), ans++;
        if(v[i] > 0)
            swap(v[i], v[i+1]), ans++; // it means first shoe is right part
    }
    return ans;
}

int main(){
    ll answer = count_swaps({2, 1, -1, -2});
    printf("%lld\n", answer);
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:35:21: warning: 'ad' may be used uninitialized in this function [-Wmaybe-uninitialized]
   35 |             swap(v[j], v[j-1]), ans++;
      |                     ^
/usr/bin/ld: /tmp/ccdVzajI.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccubzFHJ.o:shoes.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status