Problem p02658 (C++)

Buggy submission (status: Runtime Error):
//  RAKSHIT KADAM
// ALWAYS USE &IT FOR ITERATING USING AUTO ...
// USE COUNT(STARTING ADDRESS, ENDING ADRESS ,VALUE) FOR FINDING THE COUNT IN
// THE RESPECTIVE DATA STRUCTURE NOTE THAT MEMSET CANNOT ASSIGN A VALUE OF 10^18
// IT WILL ASSIGN A LOWER VALUE THAN THAT!!! NOTE THAT MEMSET CANT FILL THE
// DOUBLE VALUES; ACCUMULATE DOES NOT WORK PROPERLY IF VALUES START SUMMING
// BEYOND 1E9...
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree< int ,  null_type ,  less<int> ,  rb_tree_tag ,
// tree_order_statistics_node_update>
#warning !!!check the size of arrayss!!!

// NUMERIC DEFINITIONS :
#define INF 2000000000000000005
#define MOD 1000000007
#define newMOD 998244353
#define MAX 300006
#define pi 3.1415926535897932384626433832795
#define ld long double
#define ll long long
#define int long long

#define P(gg)                                                                  \
  for (auto rax : gg) {                                                        \
    cout << rax << " ";                                                        \
  }                                                                            \
  cout << endl;
#define Need_for_speed(activated)                                              \
  ios_base ::sync_with_stdio(0);                                               \
  cin.tie(NULL);                                                               \
  cout.tie(NULL)
#define satisfy                                                                \
  ll t;                                                                        \
  cin >> t;                                                                    \
  while (t--)
#define inp(n)                                                                 \
  int n;                                                                       \
  cin >> n
#define mp make_pair
#define pb push_back
#define endl "\n"
#define x first
#define y second
#define fore(i, a, b) for (ll i = a; i < b; i++)
#define forci(i, n) for (ll i = 0; i < n; i++)
#define vi vector<ll>
#define Endl endl
#define lb lower_bound
#define ub upper_bound
#define pii pair<ll, ll>

#define input                                                                  \
  freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define time                                                                   \
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
using namespace std;

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
int power(int x, unsigned int y, unsigned int m) {
  if (y == 0)
    return 1;
  int p = power(x, y / 2, m) % m;
  p = (p * p) % m;
  return (y % 2 == 0) ? p : (x * p) % m;
}
ll modInverse(int a, int m) {
  int g = gcd(a, m);
  { return power(a, m - 2, m); }
}
const int maxn = 500004;
ll bad;
void solve() {
  ll n;
  cin >> n;
  ll ans = 1;
  ll c = 1;
  for (ll j = 1; j <= 18; j++)
    c *= 10;
  ll x;

  for (ll i = 0; i < n; i++) {
    cin >> x;
    if (ans != 0)
      if (c / ans < x) {
        bad = 1;
      }
    if (c / ans >= x) {
      ans *= x;
    }
    if (x == 0)
      bad = 0, ans = 0;
  }
  if (bad)
    cout << "-1" << endl;
  else
    cout << ans << endl;
}
signed main() {
  Need_for_speed(activated);

  // satisfy
  //     {
  //    solve();
  //    }

  solve();
  return 0;
}


Fixed submission:
//  RAKSHIT KADAM
// ALWAYS USE &IT FOR ITERATING USING AUTO ...
// USE COUNT(STARTING ADDRESS, ENDING ADRESS ,VALUE) FOR FINDING THE COUNT IN
// THE RESPECTIVE DATA STRUCTURE NOTE THAT MEMSET CANNOT ASSIGN A VALUE OF 10^18
// IT WILL ASSIGN A LOWER VALUE THAN THAT!!! NOTE THAT MEMSET CANT FILL THE
// DOUBLE VALUES; ACCUMULATE DOES NOT WORK PROPERLY IF VALUES START SUMMING
// BEYOND 1E9...
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
// #define ordered_set tree< int ,  null_type ,  less<int> ,  rb_tree_tag ,
// tree_order_statistics_node_update>
#warning !!!check the size of arrayss!!!

// NUMERIC DEFINITIONS :
#define INF 2000000000000000005
#define MOD 1000000007
#define newMOD 998244353
#define MAX 300006
#define pi 3.1415926535897932384626433832795
#define ld long double
#define ll long long
#define int long long

#define P(gg)                                                                  \
  for (auto rax : gg) {                                                        \
    cout << rax << " ";                                                        \
  }                                                                            \
  cout << endl;
#define Need_for_speed(activated)                                              \
  ios_base ::sync_with_stdio(0);                                               \
  cin.tie(NULL);                                                               \
  cout.tie(NULL)
#define satisfy                                                                \
  ll t;                                                                        \
  cin >> t;                                                                    \
  while (t--)
#define inp(n)                                                                 \
  int n;                                                                       \
  cin >> n
#define mp make_pair
#define pb push_back
#define endl "\n"
#define x first
#define y second
#define fore(i, a, b) for (ll i = a; i < b; i++)
#define forci(i, n) for (ll i = 0; i < n; i++)
#define vi vector<ll>
#define Endl endl
#define lb lower_bound
#define ub upper_bound
#define pii pair<ll, ll>

#define input                                                                  \
  freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define time                                                                   \
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
using namespace std;

ll gcd(ll a, ll b) {
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
int power(int x, unsigned int y, unsigned int m) {
  if (y == 0)
    return 1;
  int p = power(x, y / 2, m) % m;
  p = (p * p) % m;
  return (y % 2 == 0) ? p : (x * p) % m;
}
ll modInverse(int a, int m) {
  int g = gcd(a, m);
  { return power(a, m - 2, m); }
}
const int maxn = 500004;
ll bad;
void solve() {
  ll n;
  cin >> n;
  ll ans = 1;
  ll c = 1;
  for (ll j = 1; j <= 18; j++)
    c *= 10;
  ll x;

  for (ll i = 0; i < n; i++) {
    cin >> x;
    if (ans != 0)
      if (c / ans < x) {
        bad = 1;
      }
    if (ans != 0)
      if (c / ans >= x) {
        ans *= x;
      }
    if (x == 0)
      bad = 0, ans = 0;
  }
  if (bad)
    cout << "-1" << endl;
  else
    cout << ans << endl;
}
signed main() {
  Need_for_speed(activated);

  // satisfy
  //     {
  //    solve();
  //    }

  solve();
  return 0;
}