Problem p02652 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define VAR(v, i) __typeof(i) v = (i)
#define FORE(i, c) for (VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
template <typename TH> void _dbg(const char *sdbg, TH h) {
  cerr << sdbg << "=" << h << "\\n";
}
template <typename TH, typename... TA>
void _dbg(const char *sdbg, TH h, TA... t) {
  while (*sdbg != ',') {
    cerr << *sdbg++;
  }
  cerr << "=" << h << ",";
  _dbg(sdbg + 1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x)                                                              \\
  {                                                                            \\
    {                                                                          \\
      cerr << #x << " = ";                                                     \\
      FORE(itt, (x)) cerr << *itt << ", ";                                     \\
      cerr << "\\n";                                                            \\
    }                                                                          \\
  }
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr                                                                   \\
  if (0)                                                                       \\
  cout
#endif
#define next ____next
#define prev ____prev
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int>> VPII;
typedef vector<pair<ll, ll>> VPLL;

template <class C> void mini(C &a4, C b4) { a4 = min(a4, b4); }
template <class C> void maxi(C &a4, C b4) { a4 = max(a4, b4); }
template <class T1, class T2>
ostream &operator<<(ostream &out, pair<T1, T2> pair) {
  return out << "(" << pair.first << ", " << pair.second << ")";
}
template <class A, class B, class C> struct Triple {
  A first;
  B second;
  C third;
  bool operator<(const Triple &t) const {
    if (st != t.st)
      return st < t.st;
    if (nd != t.nd)
      return nd < t.nd;
    return rd < t.rd;
  }
};
template <class T> void ResizeVec(T &, vector<int>) {}
template <class T> void ResizeVec(vector<T> &vec, vector<int> sz) {
  vec.resize(sz[0]);
  sz.erase(sz.begin());
  if (sz.empty()) {
    return;
  }
  for (T &v : vec) {
    ResizeVec(v, sz);
  }
}
typedef Triple<int, int, int> TIII;
template <class A, class B, class C>
ostream &operator<<(ostream &out, Triple<A, B, C> t) {
  return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")";
}
template <class T> ostream &operator<<(ostream &out, vector<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class T> ostream &operator<<(ostream &out, set<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class L, class R> ostream &operator<<(ostream &out, map<L, R> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}

struct Node {
  // int mi, ma;
  int mi, ma;
  int wh_ma;
  // int suf_mi, suf_ma;
  int to_push;
};

const int M = 1 << 20;
Node drz[2 * M + 5];

void Shift(int son, int val) {
  drz[son].mi += val;
  drz[son].ma += val;
  drz[son].to_push += val;
}

void Touch(int v) {
  FOR(son, 2 * v, 2 * v + 1) { Shift(son, drz[v].to_push); }
  drz[v].to_push = 0;
}
Node Merge(Node L, Node R) {
  Node n;
  n.mi = min(L.mi, R.mi);
  n.ma = max(L.ma, R.ma);
  if (L.ma >= R.ma) {
    n.wh_ma = L.wh_ma;
  } else {
    n.wh_ma = R.wh_ma;
  }
  n.to_push = 0;
  // n.suf_mi
  // n.sum = L.sum + R.sum;
  //    n.mi = min({L.mi, R.mi, n.pref_mi});
  //    n.ma = max(
  return n;
}
void Add(int bl, int br, int l, int r, int v, int val) {
  if (bl > r || br < l) {
    return;
  }
  if (l <= bl && br <= r) {
    Shift(v, val);
    return;
  }
  int m = (bl + br) / 2;
  Touch(v);
  Add(bl, m, l, r, 2 * v, val);
  Add(m + 1, br, l, r, 2 * v + 1, val);
  drz[v] = Merge(drz[2 * v], drz[2 * v + 1]);
}

int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  // double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;

  string s;
  set<int> or_pos;
  cin >> s;
  int n = SZ(s);
  s = "$" + s;
  VI or_prefs(n + 2);
  RE(i, n) {
    if (s[i] == '?') {
      or_pos.insert(i);
      s[i] = '1';
    }
    if (s[i] == '1') {
      or_prefs[i] = or_prefs[i - 1] + 1;
    } else {
      or_prefs[i] = or_prefs[i - 1] - 1;
    }
  }
  debug(n);
  int res = n;
  REP(tr, 2) {
    set<int> pos = or_pos;
    // VI prefs = or_prefs;
    // vector<Node> drz(2 * M + 5);
    RE(i, n) {
      int add = ((or_prefs[i] % 2) == tr);
      drz[i + M] = {or_prefs[i], or_prefs[i] + add, i, 0};
      if (i == n) {
        debug(or_prefs[i] + add);
      }
    }
    drz[M] = {0, tr == 0, 0, 0};
    FORD(i, M - 1, 0) {
      drz[i] = Merge(drz[2 * i], drz[2 * i + 1]);
      //       drz[i].mi = min(drz[2 * i].mi, drz[2 * i + 1].mi);
      //       drz[i].ma = max(drz[2 * i].ma, drz[2 * i + 1].ma);
      //       if (drz[2 * i].ma >= drz[2 * i + 1].ma) {
      //         drz[i].wh_ma = drz[2 * i].wh_ma;
      //       } else {
      //         drz[i].wh_ma = drz[2 * i + 1].wh_ma;
      //       }
      //       drz[i].to_push = 0;
    }
    mini(res, drz[1].ma - drz[1].mi);
    debug(drz[1].ma, drz[1].mi);
    while (drz[1].ma >= 2) {
      auto it = pos.upper_bound(drz[1].wh_ma);
      if (it == pos.begin()) {
        break;
      }
      it--;
      Add(0, M - 1, *it, n, 1, -2);
      debug(*it, drz[1].ma, drz[1].mi);
      pos.erase(it);
      mini(res, drz[1].ma - drz[1].mi);
    }
  }
  cout << res << endl;

  return 0;
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
#define MP make_pair
#define PB push_back
#define int long long
#define st first
#define nd second
#define rd third
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define RE(i, n) FOR(i, 1, n)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define VAR(v, i) __typeof(i) v = (i)
#define FORE(i, c) for (VAR(i, (c).begin()); i != (c).end(); ++i)
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define __builtin_ctz __builtin_ctzll
#define __builtin_clz __builtin_clzll
#define __builtin_popcount __builtin_popcountll
using namespace std;
template <typename TH> void _dbg(const char *sdbg, TH h) {
  cerr << sdbg << "=" << h << "\\n";
}
template <typename TH, typename... TA>
void _dbg(const char *sdbg, TH h, TA... t) {
  while (*sdbg != ',') {
    cerr << *sdbg++;
  }
  cerr << "=" << h << ",";
  _dbg(sdbg + 1, t...);
}
#ifdef LOCAL
#define debug(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define debugv(x)                                                              \\
  {                                                                            \\
    {                                                                          \\
      cerr << #x << " = ";                                                     \\
      FORE(itt, (x)) cerr << *itt << ", ";                                     \\
      cerr << "\\n";                                                            \\
    }                                                                          \\
  }
#else
#define debug(...) (__VA_ARGS__)
#define debugv(x)
#define cerr                                                                   \\
  if (0)                                                                       \\
  cout
#endif
#define left ____left
#define hash ____hash
typedef long long ll;
typedef long double LD;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VLL;
typedef vector<pair<int, int>> VPII;
typedef vector<pair<ll, ll>> VPLL;

template <class C> void mini(C &a4, C b4) { a4 = min(a4, b4); }
template <class C> void maxi(C &a4, C b4) { a4 = max(a4, b4); }
template <class T1, class T2>
ostream &operator<<(ostream &out, pair<T1, T2> pair) {
  return out << "(" << pair.first << ", " << pair.second << ")";
}
template <class A, class B, class C> struct Triple {
  A first;
  B second;
  C third;
  bool operator<(const Triple &t) const {
    if (st != t.st)
      return st < t.st;
    if (nd != t.nd)
      return nd < t.nd;
    return rd < t.rd;
  }
};
template <class T> void ResizeVec(T &, vector<int>) {}
template <class T> void ResizeVec(vector<T> &vec, vector<int> sz) {
  vec.resize(sz[0]);
  sz.erase(sz.begin());
  if (sz.empty()) {
    return;
  }
  for (T &v : vec) {
    ResizeVec(v, sz);
  }
}
typedef Triple<int, int, int> TIII;
template <class A, class B, class C>
ostream &operator<<(ostream &out, Triple<A, B, C> t) {
  return out << "(" << t.st << ", " << t.nd << ", " << t.rd << ")";
}
template <class T> ostream &operator<<(ostream &out, vector<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class T> ostream &operator<<(ostream &out, set<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class L, class R> ostream &operator<<(ostream &out, map<L, R> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}

const int N = 1e6 + 22;
const int L = 20;
const int P = 1e9 + 7;
int spow(int a, int b) {
  int r = 1;
  while (b) {
    if (b % 2) {
      r = r * a % P;
    }
    a = a * a % P;
    b /= 2;
  }
  return r;
}
int cnt[N];
struct Sol {
  void Test() {
    int n, p;
    cin >> n >> p;
    // map<int, int> cnt;

    set<int> ls;
    RE(i, n) {
      int k;
      cin >> k;
      cnt[k]++;
      ls.insert(k);
    }
    set<int> or_ls = ls;
    if (p == 1) {
      cout << n % 2 << "\\n";
      for (auto l : or_ls) {
        cnt[l] = 0;
      }
      return;
    }
    while (1) {
      if (ls.empty()) {
        for (auto l : or_ls) {
          // if (cnt[
          cnt[l] = 0;
        }
        cout << "0\\n";
        return;
      }
      auto it = prev(ls.end());
      int val = *it;
      debug(val, cnt[val]);
      if (cnt[*it] % 2 == 0) {
        cnt[*it] = 0;
        ls.erase(it);
      } else {
        cnt[val] = 1;
        int need = 1;
        FORD(i, val - 1, -1) {
          need *= p;
          if (need > n || i == -1) {
            int res = spow(p, val);
            int to_sub = 0;
            debug(ls);
            for (auto l : ls) {
              if (l < val) {
                to_sub = (to_sub + cnt[l] * spow(p, l)) % P;
              }
            }
            debug(res, to_sub);
            for (auto l : or_ls) {
              cnt[l] = 0;
            }
            cout << (res - to_sub + P) % P << "\\n";
            return;
          } else {
            int here = min(need, cnt[i]);
            need -= here;
            debug(here, i, val, need);
            if (need == 0) {
              cnt[i] -= here;
              FOR(j, i + 1, val) {
                ls.erase(j);
                cnt[j] = 0;
              }
              break;
            }
          }
        }
      }
    }
  }
};

int32_t main() {

  ios_base::sync_with_stdio(0);
  cout << fixed << setprecision(10);
  cerr << fixed << setprecision(10);
  cin.tie(0);
  // double beg_clock = 1.0 * clock() / CLOCKS_PER_SEC;

  int t;
  cin >> t;
  RE(i, t) {
    Sol sol;
    sol.Test();
  }

  return 0;
}