Problem p02609 (C++) — buggy submission, verdict: Runtime Error

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

#define rep(i, n) for (int i = 0; i < n; ++i)
#define ALL(a) (a).begin(), (a).end()
#define rALL(a) (a).rbegin(), (a).rend()
#define SZ(x) ((int)(x).size())
using ll = long long;
using ull = unsigned long long;
using P = pair<int, int>;
using llP = pair<ll, ll>;
using DoP = pair<double, double>;
const int di[] = {0, 1, 0, -1, 1, 1, -1, -1};
const int dj[] = {1, 0, -1, 0, 1, -1, 1, -1};
const int INF = 1 << 28;
const ll INF64 = 1ll << 55;
const int mod = 1000000007;
// const int mod = 998244353;

template <class T> inline bool chmin(T &a, const T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline void line_out(const vector<T> vec) {
  int n = SZ(vec);
  rep(i, n) {
    cout << vec[i];
    if (i < n - 1)
      cout << " ";
  }
  cout << endl;
  return;
}

struct mint {
  ll x; // typedef long long ll;
  mint(ll x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint &operator++() {
    if ((x += 1) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator--() {
    if ((x += mod - 1) >= mod)
      x -= mod;
    return *this;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const { return pow(mod - 2); }
  mint &operator/=(const mint a) { return (*this) *= a.inv(); }
  mint operator/(const mint a) const {
    mint res(*this);
    return res /= a;
  }
};

int main() {
  int n;
  string s;
  cin >> n >> s;
  reverse(ALL(s));
  int p = 0;
  rep(i, n) if (s[i] == '1')++ p;

  vector<int> inc(n), dec(n);
  int inc_x = 0, dec_x = 0;
  int add = 1;
  rep(i, n) {
    inc[i] = add;
    if (s[i] == '1') {
      inc_x += add;
      inc_x %= p + 1;
    }
    add *= 2;
    add %= p + 1;
  }
  add = 1;
  if (p - 1 > 0) {
    rep(i, n) {
      dec[i] = add;
      if (s[i] == '1') {
        dec_x += add;
        dec_x %= p - 1;
      }
      add *= 2;
      add %= p - 1;
    }
  }
  vector<int> ans(n);

  rep(i, n) {
    if (s[i] == '1') {
      if (p - 1 == 0) {
        ans[i] = 0;
        continue;
      } else if (p - 1 == 1) {
        ans[i] = 1;
        continue;
      }
      int init = dec_x - dec[i];
      init = (init + p - 1) % (p - 1);
      int res = 1;
      while (init != 0) {
        int c = bitset<30>(init).count();
        init %= c;
        ++res;
      }
      ans[i] = res;
    }

    if (s[i] == '0') {
      int init = inc_x + inc[i];
      init %= p + 1;
      int res = 1;
      if (p + 1 == 1) {
        ans[i] = 1;
        continue;
      }
      while (init != 0) {
        int c = bitset<30>(init).count();
        init %= c;
        ++res;
      }
      ans[i] = res;
    }
  }
  reverse(ALL(ans));
  for (auto x : ans)
    cout << x << endl;
}

Error: 0

Fixed submission:

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

#define rep(i, n) for (int i = 0; i < n; ++i)
#define ALL(a) (a).begin(), (a).end()
#define rALL(a) (a).rbegin(), (a).rend()
#define SZ(x) ((int)(x).size())
using ll = long long;
using ull = unsigned long long;
using P = pair<int, int>;
using llP = pair<ll, ll>;
using DoP = pair<double, double>;
const int di[] = {0, 1, 0, -1, 1, 1, -1, -1};
const int dj[] = {1, 0, -1, 0, 1, -1, 1, -1};
const int INF = 1 << 28;
const ll INF64 = 1ll << 55;
const int mod = 1000000007;
// const int mod = 998244353;

template <class T> inline bool chmin(T &a, const T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, const T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline void line_out(const vector<T> vec) {
  int n = SZ(vec);
  rep(i, n) {
    cout << vec[i];
    if (i < n - 1)
      cout << " ";
  }
  cout << endl;
  return;
}

struct mint {
  ll x; // typedef long long ll;
  mint(ll x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint a) {
    if ((x += a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator-=(const mint a) {
    if ((x += mod - a.x) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint &operator++() {
    if ((x += 1) >= mod)
      x -= mod;
    return *this;
  }
  mint &operator--() {
    if ((x += mod - 1) >= mod)
      x -= mod;
    return *this;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(ll t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const { return pow(mod - 2); }
  mint &operator/=(const mint a) { return (*this) *= a.inv(); }
  mint operator/(const mint a) const {
    mint res(*this);
    return res /= a;
  }
};

int main() {
  int n;
  string s;
  cin >> n >> s;
  reverse(ALL(s));
  int p = 0;
  rep(i, n) if (s[i] == '1')++ p;

  if (s == "1") {
    cout << 1 << endl;
    return 0;
  }

  vector<int> inc(n), dec(n);
  int inc_x = 0, dec_x = 0;
  int add = 1;
  rep(i, n) {
    inc[i] = add;
    if (s[i] == '1') {
      inc_x += add;
      inc_x %= p + 1;
    }
    add *= 2;
    add %= p + 1;
  }
  add = 1;
  rep(i, n) {
    dec[i] = add;
    if (s[i] == '1') {
      dec_x += add;
      dec_x %= p - 1;
    }
    add *= 2;
    add %= p - 1;
  }
  vector<int> ans(n);
  rep(i, n) {
    if (s[i] == '1') {
      int init = dec_x - dec[i];
      init = (init + p - 1) % (p - 1);
      int res = 1;
      while (init != 0) {
        int c = bitset<30>(init).count();
        init %= c;
        ++res;
      }
      ans[i] = res;
    }

    if (s[i] == '0') {
      int init = inc_x + inc[i];
      init %= p + 1;
      int res = 1;
      while (init != 0) {
        int c = bitset<30>(init).count();
        init %= c;
        ++res;
      }
      ans[i] = res;
    }
  }
  reverse(ALL(ans));
  for (auto x : ans)
    cout << x << endl;
}