Problem p02628 (C++)

Buggy submission (status: Runtime Error):
#pragma region header
#include <assert.h>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdint>
#include <cstdio>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <math.h>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
#define int long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define rev(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define rev1(i, n) for (int i = (int)(n); i > 0; i--)
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define resort(v) sort((v).rbegin(), (v).rend())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vs vector<string>
#define vvs vector<vector<string>>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
using ll = long long;
using P = pair<int, int>;
/* ----------------よく使う数字や配列----------------- */
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
constexpr ll mod = 1e9 + 7;
constexpr ll inf = INT32_MAX / 2;
constexpr ll INF = LLONG_MAX / 2;
constexpr long double eps = DBL_EPSILON;
constexpr long double pi = 3.141592653589793238462643383279;
/* ----------------------end----------------------- */

/* --------------------テンプレート------------------ */
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
/* ----------------------end----------------------- */

/* --------------------ライブラリ-------------------- */
ll fact(int i) { // 階乗
  if (i == 0)
    return 1;
  return (fact(i - 1)) * i % mod;
}
ll gcd(ll a, ll b) { // 最大公約数
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { // 最小公倍数
  return a * b / gcd(a, b);
}
int keta(ll n) { // 桁数を求める
  if (n == 0)
    return 1;
  int count = 0;
  while (n != 0) {
    n /= 10;
    count++;
  }
  return count;
}
bool isprime(ll a) // 素数判定、primeならtrue,違うならfalse
{
  if (a < 2)
    return false;
  else if (a == 2)
    return true;
  else if (a % 2 == 0)
    return false;
  double m = sqrt(a);
  for (int i = 3; i <= m; i += 2) {
    if (a % i == 0) {
      return false;
    }
  }

  // 素数である
  return true;
}
ll ketasum(ll n) { // 各桁の和
  ll sum = 0;
  while (n != 0) {
    sum += n % 10;
    n /= 10;
  }
  return sum;
}
#define double long double
/* ----------------------end----------------------- */
#pragma endregion
signed main() {
  int N, K;
  cin >> N >> K;
  vi fruit(N);
  rep(i, N) { cin >> fruit.at(i); }
  all(fruit);
  cout << fruit.at(0) + fruit.at(1) + fruit.at(2) << endl;
}


Fixed submission:
#pragma region header
#include <assert.h>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdint>
#include <cstdio>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <math.h>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
#define int long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i <= (int)(n); i++)
#define rev(i, n) for (int i = (int)(n - 1); i >= 0; i--)
#define rev1(i, n) for (int i = (int)(n); i > 0; i--)
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define resort(v) sort((v).rbegin(), (v).rend())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vs vector<string>
#define vvs vector<vector<string>>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
using ll = long long;
using P = pair<int, int>;
/* ----------------よく使う数字や配列----------------- */
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
constexpr ll mod = 1e9 + 7;
constexpr ll inf = INT32_MAX / 2;
constexpr ll INF = LLONG_MAX / 2;
constexpr long double eps = DBL_EPSILON;
constexpr long double pi = 3.141592653589793238462643383279;
/* ----------------------end----------------------- */

/* --------------------テンプレート------------------ */
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
/* ----------------------end----------------------- */

/* --------------------ライブラリ-------------------- */
ll fact(int i) { // 階乗
  if (i == 0)
    return 1;
  return (fact(i - 1)) * i % mod;
}
ll gcd(ll a, ll b) { // 最大公約数
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) { // 最小公倍数
  return a * b / gcd(a, b);
}
int keta(ll n) { // 桁数を求める
  if (n == 0)
    return 1;
  int count = 0;
  while (n != 0) {
    n /= 10;
    count++;
  }
  return count;
}
bool isprime(ll a) // 素数判定、primeならtrue,違うならfalse
{
  if (a < 2)
    return false;
  else if (a == 2)
    return true;
  else if (a % 2 == 0)
    return false;
  double m = sqrt(a);
  for (int i = 3; i <= m; i += 2) {
    if (a % i == 0) {
      return false;
    }
  }

  // 素数である
  return true;
}
ll ketasum(ll n) { // 各桁の和
  ll sum = 0;
  while (n != 0) {
    sum += n % 10;
    n /= 10;
  }
  return sum;
}
#define double long double
/* ----------------------end----------------------- */
#pragma endregion
signed main() {
  int N, K;
  cin >> N >> K;
  vi fruit(N);
  rep(i, N) { cin >> fruit.at(i); }
  sort(fruit.begin(), fruit.end());
  int sum = 0;
  rep(i, K) { sum += fruit.at(i); }
  cout << sum << endl;
}