Problem p02719 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1000000001;
double pi = 3.141592653589793238462643383279L;
double eps = 1e-14;
#define rep(i, m, n) for (ll i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto itr = mp.begin(); itr != mp.end(); itr++)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
int dh[4] = {1, -1, 0, 0};
int dw[4] = {0, 0, 1, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
ll gcd(ll a, ll b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll n, k;
  cin >> n >> k;
  ll u = n % k;
  cout << min(u, k - u) << endl;
}


Error: 0

Fixed submission:

#include <bits/stdc++.h>
// ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
// clock_t start=clock();clock_t
// end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef int ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef pair<pii, int> ppii;
typedef pair<int, pii> pipi;
typedef pair<ll, ll> pll;
typedef pair<pll, ll> ppll;
typedef pair<ll, pll> plpl;
typedef tuple<ll, ll, ll> tl;
typedef pair<double, double> pdd;
typedef vector<vector<ll>> mat;
ll mod = 1000000007;
ll mod2 = 998244353;
ll mod3 = 1000003;
ll mod4 = 998244853;
ll mod5 = 1000000009;
ll inf = 1000000001;
double pi = 3.141592653589793238462643383279L;
double eps = 1e-14;
#define rep(i, m, n) for (ll i = m; i < n; i++)
#define rrep(i, n, m) for (ll i = n; i >= m; i--)
#define srep(itr, st) for (auto itr = st.begin(); itr != st.end(); itr++)
#define mrep(itr, mp) for (auto itr = mp.begin(); itr != mp.end(); itr++)
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
int dh[4] = {1, -1, 0, 0};
int dw[4] = {0, 0, 1, -1};
int ddh[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int ddw[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
ll gcd(ll a, ll b) {
  if (a < b)
    swap(a, b);
  if (b == 0)
    return a;
  if (a % b == 0)
    return b;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  ll c = gcd(a, b);
  return a * b / c;
}
ll Pow(ll n, ll k) {
  ll ret = 1;
  ll now = n;
  while (k > 0) {
    if (k & 1)
      ret *= now;
    now *= now;
    k /= 2;
  }
  return ret;
}
ll beki(ll n, ll k, ll md) {
  ll ret = 1;
  ll now = n;
  now %= md;
  while (k > 0) {
    if (k % 2 == 1) {
      ret *= now;
      ret %= md;
    }
    now *= now;
    now %= md;
    k /= 2;
  }
  return ret;
}
ll gyaku(ll n, ll md) { return beki(n, md - 2, md); }
ll popcount(ll n) {
  ll ret = 0;
  ll u = n;
  while (u > 0) {
    ret += u % 2;
    u /= 2;
  }
  return ret;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ll n, k;
  cin >> n >> k;
  cout << min(n % k, k - n % k) << endl;
}