The code below getting runtime error in codeforces after submission but runs okay in vs code. Can anyone kindly help why is this code getting runtime error? //#pragma GCC optimize("Ofast")

include <bits/stdc++.h>

define t_st clock_t start = clock();

define t_en clock_t stop = clock();

define t_p double duration = double(stop-start) / double(CLOCKS_PER_SEC); printf("RUNTIME: %.10f\n",duration);

define endline "\n"

define ulli unsigned long long int //64

define lli long long int //64

define uli unsigned long int //32

define li long int //32

define pi 3.1415926535897932384626433832795

using namespace std;

// SOLVE : https://codeforces.me/problemset/problem/1195/A void solve(int n, int k) { int sets = (int)ceil(n / 2.0); int no = 0;

vector<int> count(1001);
vector< pair<int,int> > c_tp;

for(int i = 1; i <= n; i++)
{
    int x;
    cin >> x;
    ++count[x];
}

for (int i = 1; i <= k; ++i)
{
    if(count[i] > 0)
    {
        c_tp.push_back({count[i], i});
    }
}

sort(c_tp.begin(), c_tp.end());


for(int i = c_tp.size() - 1; i >= 0 && sets > 0; --i)
{
    if(c_tp[i].first > 0)
    {
        if((c_tp[i].first&1) == 1 && c_tp[i - 1].first > 0)
        {
            ++no;
            --c_tp[i - 1].first;   
        }
        --sets;
    }
}

cout << (n - no) << endline;

}

int main() { ios_base::sync_with_stdio(false); cin.tie(NULL);

#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
t_st
#endif

int test = 1, n, k;
//cin >> test;

while(test--)
{
    cin >> n >> k;
    solve(n, k);
}

#ifndef ONLINE_JUDGE
t_en
t_p
#endif


return 0;

}