Problem p02578 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>

const double pi = 3.141592653589793238462643383279;
using namespace std;

// typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SQ(a) ((a) * (a))
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define MOD 1000000007

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
const long double EPS = 1e-6, PI = acos((long double)-1);

// ここから編集
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(4);

  int N;
  cin >> N;
  vector<ll> v(N);

  REP(i, N) cin >> v[i];

  ll ans = 0;
  ll mx = v[0];
  for (int i = 1; i < N; i++) {
    ans += max(0LL, mx - v[i]);
    mx = max(mx, v[i]);
  }
  cout << ans << endl;
  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>

const double pi = 3.141592653589793238462643383279;
using namespace std;

// typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long> PLL;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

// container util
//------------------------------------------
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SQ(a) ((a) * (a))
#define EACH(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort((c).begin(), (c).end())

// repetition
//------------------------------------------
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define MOD 1000000007

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
const long double EPS = 1e-6, PI = acos((long double)-1);

// ここから編集
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(4);

  int N;
  vector<ll> v(N);
  cin >> N;
  REP(i, N) cin >> v[i];

  ll ans = 0;
  ll mx = v[0];
  for (int i = 1; i < N; i++) {
    ans += max(0LL, mx - v[i]);
    mx = max(mx, v[i]);
  }
  cout << ans << endl;
  return 0;
}