Problem p01288 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#define int long long // <-----!!!!!!!!!!!!!!!!!!!

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
#define rrep2(i, a, b) for (int i = (a)-1; i >= b; i--)
#define chmin(a, b) (a) = min((a), (b));
#define chmax(a, b) (a) = max((a), (b));
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define printV(v)                                                              \\
  cout << (#v) << ":";                                                         \\
  for (auto(x) : (v)) {                                                        \\
    cout << " " << (x);                                                        \\
  }                                                                            \\
  cout << endl;
#define printVS(vs)                                                            \\
  cout << (#vs) << ":" << endl;                                                \\
  for (auto(s) : (vs)) {                                                       \\
    cout << (s) << endl;                                                       \\
  }
#define printVV(vv)                                                            \\
  cout << (#vv) << ":" << endl;                                                \\
  for (auto(v) : (vv)) {                                                       \\
    for (auto(x) : (v)) {                                                      \\
      cout << " " << (x);                                                      \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define printP(p) cout << (#p) << (p).first << " " << (p).second << endl;
#define printVP(vp)                                                            \\
  cout << (#vp) << ":" << endl;                                                \\
  for (auto(p) : (vp)) {                                                       \\
    cout << (p).first << " " << (p).second << endl;                            \\
  }

inline void output() { cout << endl; }
template <typename First, typename... Rest>
inline void output(const First &first, const Rest &...rest) {
  cout << first << " ";
  output(rest...);
}

using ll = long long;
using Pii = pair<int, int>;
using TUPLE = tuple<int, int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
const int inf = 1ll << 60;
const int mod = 1e9 + 7;
using Graph = vector<vector<int>>;

int n, q;
vi par;
vector<char> t;
vi v;
vi cnt;

int lma(int x) {
  if (cnt[x])
    return x;
  return par[x] = lma(par[x]);
}

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

  while (cin >> n >> q, n) {
    par.assign(n, -1);
    rep2(i, 1, n) {
      int p;
      cin >> p;
      p--;
      par[i] = p;
    }

    t.clear();
    t.resize(n);
    v.clear();
    v.resize(n);
    cnt.assign(n, 0);
    cnt[0] = 1;
    rep(i, q) {
      cin >> t[i] >> v[i];
      v[i]--;
      if (t[i] == 'M') {
        cnt[v[i]]++;
      }
    }

    int ans = 0;
    rrep(i, q) {
      if (t[i] == 'M') {
        cnt[v[i]]--;
      } else {
        ans += lma(v[i]) + 1;
      }
    }
    cout << ans << endl;
  }
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#define int long long // <-----!!!!!!!!!!!!!!!!!!!

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
#define rrep2(i, a, b) for (int i = (a)-1; i >= b; i--)
#define chmin(a, b) (a) = min((a), (b));
#define chmax(a, b) (a) = max((a), (b));
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define printV(v)                                                              \\
  cout << (#v) << ":";                                                         \\
  for (auto(x) : (v)) {                                                        \\
    cout << " " << (x);                                                        \\
  }                                                                            \\
  cout << endl;
#define printVS(vs)                                                            \\
  cout << (#vs) << ":" << endl;                                                \\
  for (auto(s) : (vs)) {                                                       \\
    cout << (s) << endl;                                                       \\
  }
#define printVV(vv)                                                            \\
  cout << (#vv) << ":" << endl;                                                \\
  for (auto(v) : (vv)) {                                                       \\
    for (auto(x) : (v)) {                                                      \\
      cout << " " << (x);                                                      \\
    }                                                                          \\
    cout << endl;                                                              \\
  }
#define printP(p) cout << (#p) << (p).first << " " << (p).second << endl;
#define printVP(vp)                                                            \\
  cout << (#vp) << ":" << endl;                                                \\
  for (auto(p) : (vp)) {                                                       \\
    cout << (p).first << " " << (p).second << endl;                            \\
  }

inline void output() { cout << endl; }
template <typename First, typename... Rest>
inline void output(const First &first, const Rest &...rest) {
  cout << first << " ";
  output(rest...);
}

using ll = long long;
using Pii = pair<int, int>;
using TUPLE = tuple<int, int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
const int inf = 1ll << 60;
const int mod = 1e9 + 7;
using Graph = vector<vector<int>>;

int n, q;
vi par;
vector<char> t;
vi v;
vi cnt;

int lma(int x) {
  if (cnt[x])
    return x;
  return par[x] = lma(par[x]);
}

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

  while (cin >> n >> q, n) {
    par.assign(n, -1);
    rep(i, n - 1) {
      int p;
      cin >> p;
      p--;
      par[i] = p;
    }

    t.clear();
    t.resize(n);
    v.clear();
    v.resize(n);
    cnt.assign(n, 0);
    cnt[0] = 1;
    rep(i, q) {
      cin >> t[i] >> v[i];
      v[i]--;
      if (t[i] == 'M') {
        cnt[v[i]]++;
      }
    }

    int ans = 0;
    rrep(i, q) {
      if (t[i] == 'M') {
        cnt[v[i]]--;
      } else {
        ans += lma(v[i]) + 1;
      }
    }
    cout << ans << endl;
  }
}