Problem p02615 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#define rep(i, a, b) for (auto i = (a); i < (b); i++)
#define per(i, a, b) for (auto i = (a); i >= (b); i--)
#define Min(a, b) ((a) < (b) ? (a) : (b))
#define Max(a, b) ((a) > (b) ? (a) : (b))
#define int_inf 0x3f3f3f3f
#define int_max 2147483647
#define ll_max 9223372036854775807
#define ull_max 18446744073709551615
#define ll_inf 0x7f7f7f7f7f7f7f7f
#define lowbit(x) (x) & (-x)
#define mp make_pair
#define fi first
#define se second
#define pb push_back
#define eps 1e-8
#define all(v) (v.begin(), v.end())
#define db double
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
const ll mod = 1e9 + 7;
const double pi = acos(-1.0);
const double inf = 1e100;
template <class T> inline T read() {
  T x = 0, f = 1;
  char s = getchar();
  while (s < '0' || s > '9') {
    if (s == '-')
      f = -1;
    s = getchar();
  };
  while (s >= '0' && s <= '9') {
    x = (x << 3) + (x << 1) + s - 48;
    s = getchar();
  };
  return x * f;
}
template <typename T> inline void wri(T x) {
  if (x < 0) {
    x = -x;
    putchar('-');
  };
  if (x / 10)
    wri(x / 10);
  putchar(x % 10 + 48);
}
template <typename T> inline void print(T x, char s) {
  wri(x);
  putchar(s);
}
template <typename T> T gcd(T a, T b) { return b == 0 ? a : gcd(b, a % b); }
// 关闭流同步就不能手写读入优化啦
int a[200010];
int n;
bool cmp(int a, int b) { return a > b; }
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> n;
  rep(i, 1, n + 1) cin >> a[i];
  sort(a + 1, a + 1 + n, cmp);
  ll ans = 0;
  int cnt = n - 1;
  if (cnt) {
    ans += a[1];
    cnt--;
    int pos = 2;
    while (cnt) {
      ans += a[pos];
      cnt--;
      if (!cnt)
        break;
      ans += a[pos];
      cnt--;
      pos++;
    }
  }
  cout << ans << endl;
  return 0;
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, a, b) for (auto i = (a); i < (b); i++)
#define per(i, a, b) for (auto i = (a); i >= (b); i--)
#define Min(a, b) ((a) < (b) ? (a) : (b))
#define Max(a, b) ((a) > (b) ? (a) : (b))
#define int_inf 0x3f3f3f3f
#define int_max 2147483647
#define ll_max 9223372036854775807
#define ull_max 18446744073709551615
#define ll_inf 0x7f7f7f7f7f7f7f7f
#define lowbit(x) (x) & (-x)
#define mp make_pair
#define fi first
#define se second
#define pb push_back
#define eps 1e-8
#define all(v) (v.begin(), v.end())
#define db double
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
const ll mod = 1e9 + 7;
const double pi = acos(-1.0);
const double inf = 1e100;
template <class T> inline T read() {
  T x = 0, f = 1;
  char s = getchar();
  while (s < '0' || s > '9') {
    if (s == '-')
      f = -1;
    s = getchar();
  };
  while (s >= '0' && s <= '9') {
    x = (x << 3) + (x << 1) + s - 48;
    s = getchar();
  };
  return x * f;
}
template <typename T> inline void wri(T x) {
  if (x < 0) {
    x = -x;
    putchar('-');
  };
  if (x / 10)
    wri(x / 10);
  putchar(x % 10 + 48);
}
template <typename T> inline void print(T x, char s) {
  wri(x);
  putchar(s);
}
template <typename T> T gcd(T a, T b) { return b == 0 ? a : gcd(b, a % b); }
// 关闭流同步就不能手写读入优化啦
int a[200010];
int n;
bool cmp(int a, int b) { return a > b; }
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> n;
  rep(i, 1, n + 1) cin >> a[i];
  sort(a + 1, a + 1 + n, cmp);
  int ans = 0;
  int cnt = n - 1;
  ans += a[1];
  cnt--;
  if (cnt == 1) {
    ans += a[2];
  } else {
    ans += a[2];
    cnt--;
    int pos = 2;
    while (cnt) {
      ans += a[pos];
      cnt--;
      if (!cnt)
        break;
      ans += a[pos];
      cnt--;
      pos++;
    }
  }
  cout << ans << endl;
  return 0;
}