Problem p03311 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;

// #define int long long
#define rep(i, n) for (long long i = (long long)(0); i < (long long)(n); ++i)
#define reps(i, n) for (long long i = (long long)(1); i <= (long long)(n); ++i)
#define rrep(i, n) for (long long i = ((long long)(n)-1); i >= 0; i--)
#define rreps(i, n) for (long long i = ((long long)(n)); i > 0; i--)
#define irep(i, m, n)                                                          \
  for (long long i = (long long)(m); i < (long long)(n); ++i)
#define ireps(i, m, n)                                                         \
  for (long long i = (long long)(m); i <= (long long)(n); ++i)
#define SORT(v, n) sort(v, v + n);
#define REVERSE(v, n) reverse(v, v + n);
#define vsort(v) sort(v.begin(), v.end());
#define all(v) v.begin(), v.end()
#define mp(n, m) make_pair(n, m);
#define cout(d) cout << d << endl;
#define coutd(d) cout << std::setprecision(10) << d << endl;
#define cinline(n) getline(cin, n);
#define replace_all(s, b, a) replace(s.begin(), s.end(), b, a);
#define PI (acos(-1))
#define FILL(v, n, x) fill(v, v + n, x);
#define sz(x) long long(x.size())

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vs = vector<string>;
using vpll = vector<pair<ll, ll>>;
using vtp = vector<tuple<ll, ll, ll>>;
using vb = vector<bool>;

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

const ll INF = 1e9 + 10;
const ll MOD = 1e9 + 7;
const ll LINF = 1e18;

ll n;
ll a[100005];
ll s[100005];

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;
  rep(i, n) cin >> a[i], a[i] -= (i + 1);

  SORT(a, n);
  rep(i, n) s[i + 1] = s[i] + a[i];

  ll ans = LINF;
  rep(i, n) {
    ll tmp = abs(s[i + 1] - a[i] * (i + 1)) +
             abs(s[n] - s[i + 1] - a[i] * (n - i - 1));
    chmin(ans, tmp);
  }

  cout << ans << endl;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;

// #define int long long
#define rep(i, n) for (long long i = (long long)(0); i < (long long)(n); ++i)
#define reps(i, n) for (long long i = (long long)(1); i <= (long long)(n); ++i)
#define rrep(i, n) for (long long i = ((long long)(n)-1); i >= 0; i--)
#define rreps(i, n) for (long long i = ((long long)(n)); i > 0; i--)
#define irep(i, m, n)                                                          \
  for (long long i = (long long)(m); i < (long long)(n); ++i)
#define ireps(i, m, n)                                                         \
  for (long long i = (long long)(m); i <= (long long)(n); ++i)
#define SORT(v, n) sort(v, v + n);
#define REVERSE(v, n) reverse(v, v + n);
#define vsort(v) sort(v.begin(), v.end());
#define all(v) v.begin(), v.end()
#define mp(n, m) make_pair(n, m);
#define cout(d) cout << d << endl;
#define coutd(d) cout << std::setprecision(10) << d << endl;
#define cinline(n) getline(cin, n);
#define replace_all(s, b, a) replace(s.begin(), s.end(), b, a);
#define PI (acos(-1))
#define FILL(v, n, x) fill(v, v + n, x);
#define sz(x) long long(x.size())

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vs = vector<string>;
using vpll = vector<pair<ll, ll>>;
using vtp = vector<tuple<ll, ll, ll>>;
using vb = vector<bool>;

template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}

const ll INF = 1e9 + 10;
const ll MOD = 1e9 + 7;
const ll LINF = 1e18;

ll n;
ll a[200005];
ll s[200005];

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;
  rep(i, n) cin >> a[i], a[i] -= (i + 1);

  SORT(a, n);
  rep(i, n) s[i + 1] = s[i] + a[i];

  ll ans = LINF;
  rep(i, n) {
    ll tmp = abs(s[i + 1] - a[i] * (i + 1)) +
             abs(s[n] - s[i + 1] - a[i] * (n - i - 1));
    chmin(ans, tmp);
  }

  cout << ans << endl;
}