Problem p02609 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>

using namespace std;

#define debug(n) cerr << #n << ':' << n << endl;
#define dline cerr << __LINE__ << endl;

using ll = long long;
template <class T, class U> using P = pair<T, U>;
template <class T> using Heap = priority_queue<T>;
template <class T> using heaP = priority_queue<T, vector<T>, greater<T>>;
template <class T, class U> using umap = unordered_map<T, U>;
template <class T> using uset = unordered_set<T>;

template <class T> bool ChangeMax(T &a, const T &b) {
  if (a >= b)
    return false;
  a = b;
  return true;
}

template <class T> bool ChangeMin(T &a, const T &b) {
  if (a <= b)
    return false;
  a = b;
  return true;
}

template <class T, size_t N, class U> void Fill(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &e : v)
    is >> e;
  return is;
}

int Rec(int x) {
  static int mem[200001];
  static int used[200001];
  if (used[x])
    return mem[x];
  used[x] = 1;
  if (x == 0)
    return 0;
  int cnt = __builtin_popcount(x);
  return mem[x] = Rec(x % cnt) + 1;
}

int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int cnt = 0;
  for (int i = 0; i < n; ++i)
    cnt += s[i] == '1';
  int cnti = cnt + 1;
  int cntd = cnt - 1;
  int xi = 0, xd = 0, yi = 1, yd = 1;
  int xx = 0, yy = 1;
  for (int i = n - 1; i >= 0; --i) {
    if (s[i] == '1') {
      xx += yy;
      xi = (xi + yi) % cnti;
      if (cntd > 0)
        xd = (xd + yd) % cntd;
    }
    yi = (yi * 2) % cnti;
    if (cntd > 0)
      yd = (yd * 2) % cntd;
    yy = yy * 2;
  }
  yi = yd = 1;
  vector<int> ans;
  for (int i = n - 1; i >= 0; --i) {
    if (s[i] == '1') {
      if (cntd == 0) {
        ans.push_back(0);
      } else {
        int x = (xd + cntd - yd) % cntd;
        ans.push_back(Rec(x) + 1);
      }
    } else {
      int x = (xi + yi) % cnti;
      ans.push_back(Rec(x) + 1);
    }
    yi = (yi * 2) % cnti;
    yd = (yd * 2) % cntd;
  }
  for (int i = n - 1; i >= 0; --i) {
    cout << ans[i] << endl;
  }
  return 0;
}


Fixed submission:
#include <bits/stdc++.h>

using namespace std;

#define debug(n) cerr << #n << ':' << n << endl;
#define dline cerr << __LINE__ << endl;

using ll = long long;
template <class T, class U> using P = pair<T, U>;
template <class T> using Heap = priority_queue<T>;
template <class T> using heaP = priority_queue<T, vector<T>, greater<T>>;
template <class T, class U> using umap = unordered_map<T, U>;
template <class T> using uset = unordered_set<T>;

template <class T> bool ChangeMax(T &a, const T &b) {
  if (a >= b)
    return false;
  a = b;
  return true;
}

template <class T> bool ChangeMin(T &a, const T &b) {
  if (a <= b)
    return false;
  a = b;
  return true;
}

template <class T, size_t N, class U> void Fill(T (&a)[N], const U &v) {
  fill((U *)a, (U *)(a + N), v);
}

template <class T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &e : v)
    is >> e;
  return is;
}

int Rec(int x) {
  static int mem[200001];
  static int used[200001];
  if (used[x])
    return mem[x];
  used[x] = 1;
  if (x == 0)
    return 0;
  int cnt = __builtin_popcount(x);
  return mem[x] = Rec(x % cnt) + 1;
}

int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int cnt = 0;
  for (int i = 0; i < n; ++i)
    cnt += s[i] == '1';
  int cnti = cnt + 1;
  int cntd = cnt - 1;
  int xi = 0, xd = 0, yi = 1, yd = 1;
  int xx = 0, yy = 1;
  for (int i = n - 1; i >= 0; --i) {
    if (s[i] == '1') {
      xx += yy;
      xi = (xi + yi) % cnti;
      if (cntd > 0)
        xd = (xd + yd) % cntd;
    }
    yi = (yi * 2) % cnti;
    if (cntd > 0)
      yd = (yd * 2) % cntd;
    yy = yy * 2;
  }
  yi = yd = 1;
  vector<int> ans;
  for (int i = n - 1; i >= 0; --i) {
    if (s[i] == '1') {
      if (cntd == 0) {
        ans.push_back(0);
      } else {
        int x = (xd + cntd - yd) % cntd;
        ans.push_back(Rec(x) + 1);
      }
    } else {
      int x = (xi + yi) % cnti;
      ans.push_back(Rec(x) + 1);
    }
    yi = (yi * 2) % cnti;
    if (cntd > 0)
      yd = (yd * 2) % cntd;
  }
  for (int i = n - 1; i >= 0; --i) {
    cout << ans[i] << endl;
  }
  return 0;
}