Problem p02684 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a - 1; i >= 0; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a - 1; i >= b; --i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;

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;
}

ll gcd(ll n, ll m) {
  ll tmp;
  while (m != 0) {
    tmp = n % m;
    n = m;
    m = tmp;
  }
  return n;
}

ll lcm(ll n, ll m) {
  return abs(n) / gcd(n, m) * abs(m); // gl=xy
}

using namespace std;

#define int ll

ll dp[65][200005]; // dp[i][j]:j番目の要素に対して2^i回操作を適用したときの値
void solve() {
  ll n, k;
  cin >> n >> k;
  vector<ll> a(n);
  rep(i, n) cin >> a[i], a[i]--;
  memset(dp, 0, sizeof(dp));
  rep(i, n) { dp[0][i] = a[i]; }
  rep(i, 60) {
    rep(j, n) {
      if ((1LL << (i + 1)) > k) {
        dp[i + 1][j] = -1;
      } else {
        dp[i + 1][j] = dp[i][dp[i][j]];
      }
    }
  }
  int s = 0;
  for (int i = 60; i >= 0; --i) {
    if (dp[i][s] < 0) {
      continue;
    }
    if (k & (1LL << i)) {
      s = dp[i][s];
    }
  }
  cout << s + 1;
}
#undef int

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(15);
  solve();
  return 0;
}

Error: -11

Fixed submission:

#include <bits/stdc++.h>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a - 1; i >= 0; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a - 1; i >= b; --i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;

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;
}

ll gcd(ll n, ll m) {
  ll tmp;
  while (m != 0) {
    tmp = n % m;
    n = m;
    m = tmp;
  }
  return n;
}

ll lcm(ll n, ll m) {
  return abs(n) / gcd(n, m) * abs(m); // gl=xy
}

using namespace std;

#define int ll

ll dp[100][200005]; // dp[i][j]:j番目の要素に対して2^i回操作を適用したときの値
void solve() {
  ll n, k;
  cin >> n >> k;
  vector<ll> a(n);
  rep(i, n) cin >> a[i], a[i]--;
  memset(dp, 0, sizeof(dp));
  rep(i, n) { dp[0][i] = a[i]; }
  rep(i, 100) {
    rep(j, n) {
      if ((1LL << (i + 1)) > k) {
        dp[i + 1][j] = -1;
      } else {
        dp[i + 1][j] = dp[i][dp[i][j]];
      }
    }
  }
  int s = 0;
  for (int i = 100 - 1; i >= 0; --i) {
    if (dp[i][s] < 0) {
      continue;
    }
    if (k & (1LL << i)) {
      s = dp[i][s];
    }
  }
  cout << s + 1;
}
#undef int

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(15);
  solve();
  return 0;
}