Problem p02609 (C++)

Buggy submission (status: Runtime Error):
#pragma target("avx")
#pragma optimize("O3")
#include <bits/stdc++.h>
using ll = int_fast64_t;
using P = std::pair<ll, ll>;
using PP = std::pair<ll, P>;
using V = std::vector<ll>;
template <typename T> using pq = std::priority_queue<T>;
template <typename T>
using rpq = std::priority_queue<T, std::vector<T>, std::greater<T>>;

#define REP(i, b, e) for (ll i = b; i < e; i++)
#define ALL(vec) vec.begin(), vec.end()
#define PRINT(vec)                                                             \
  printf("[ ");                                                                \
  for (auto &i : vec)                                                          \
    printf("%ld ", i);                                                         \
  puts("]");
#define SCAN(vec)                                                              \
  for (auto &i : vec)                                                          \
  scanf("%ld", &i)
#define fi first
#define se second

const int MOD = 1e9 + 7;
const ll INF = 1e18;
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

ll modpow(ll a, ll p, ll m) {
  ll ret = 1;
  while (p) {
    if (p % 2)
      ret = ret * a % m;
    a = a * a % m;
    p >>= 1;
  }
  return ret;
}

ll rec(ll m, ll ans) {
  if (m == 0)
    return ans;
  else
    return rec(m % __builtin_popcount(m), ans + 1);
}

int main() {
  int n;
  scanf("%d", &n);
  char s[n + 1];
  scanf("%s", s);
  int cnt = 0;
  REP(i, 0, n) cnt += (s[i] == '1');
  ll val_inc = 0, val_dec = 0, bi_inc = 1, bi_dec = 1;
  REP(i, 0, n) {
    if (s[n - i - 1] == '1') {
      val_dec = (val_dec + bi_dec) % (cnt - 1);
      val_inc = (val_inc + bi_inc) % (cnt + 1);
    }
    bi_dec = bi_dec * 2 % (cnt - 1);
    bi_inc = bi_inc * 2 % (cnt + 1);
  }

  REP(i, 0, n) {
    ll m, ans = 1;
    if (s[i] == '1')
      m = (val_dec - modpow(2, n - i - 1, cnt - 1) + (cnt - 1)) % (cnt - 1);
    else
      m = (val_inc + modpow(2, n - i - 1, cnt + 1)) % (cnt + 1);
    printf("%ld\n", rec(m, ans));
  }

  return 0;
}


Fixed submission:
#pragma target("avx")
#pragma optimize("O3")
#include <bits/stdc++.h>
using ll = int_fast64_t;
using P = std::pair<ll, ll>;
using PP = std::pair<ll, P>;
using V = std::vector<ll>;
template <typename T> using pq = std::priority_queue<T>;
template <typename T>
using rpq = std::priority_queue<T, std::vector<T>, std::greater<T>>;

#define REP(i, b, e) for (ll i = b; i < e; i++)
#define ALL(vec) vec.begin(), vec.end()
#define PRINT(vec)                                                             \
  printf("[ ");                                                                \
  for (auto &i : vec)                                                          \
    printf("%ld ", i);                                                         \
  puts("]");
#define SCAN(vec)                                                              \
  for (auto &i : vec)                                                          \
  scanf("%ld", &i)
#define fi first
#define se second

const int MOD = 1e9 + 7;
const ll INF = 1e18;
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

ll modpow(ll a, ll p, ll m) {
  ll ret = 1;
  while (p) {
    if (p % 2)
      ret = ret * a % m;
    a = a * a % m;
    p >>= 1;
  }
  return ret;
}

ll rec(ll m, ll ans) {
  if (m == 0)
    return ans;
  else
    return rec(m % __builtin_popcount(m), ans + 1);
}

int main() {
  int n;
  scanf("%d", &n);
  char s[n + 1];
  scanf("%s", s);
  int cnt = 0;
  REP(i, 0, n) cnt += (s[i] == '1');

  if (cnt == 0) {
    REP(i, 0, n) puts("1");
    return 0;
  } else if (cnt == 1) {
    ll val_inc = 0, bi_inc = 1;
    REP(i, 0, n) {
      if (s[n - i - 1] == '1') {
        val_inc = (val_inc + bi_inc) % (cnt + 1);
      }
      bi_inc = bi_inc * 2 % (cnt + 1);
    }

    REP(i, 0, n) {
      if (s[i] == '1')
        puts("0");
      else {
        ll m = (val_inc + modpow(2, n - i - 1, cnt + 1)) % (cnt + 1);
        printf("%ld\n", rec(m, 1));
      }
    }
    return 0;
  }

  ll val_inc = 0, val_dec = 0, bi_inc = 1, bi_dec = 1;
  REP(i, 0, n) {
    if (s[n - i - 1] == '1') {
      val_dec = (val_dec + bi_dec) % (cnt - 1);
      val_inc = (val_inc + bi_inc) % (cnt + 1);
    }
    bi_dec = bi_dec * 2 % (cnt - 1);
    bi_inc = bi_inc * 2 % (cnt + 1);
  }

  REP(i, 0, n) {
    ll m, ans = 1;
    if (s[i] == '1')
      m = (val_dec - modpow(2, n - i - 1, cnt - 1) + (cnt - 1)) % (cnt - 1);
    else
      m = (val_inc + modpow(2, n - i - 1, cnt + 1)) % (cnt + 1);
    printf("%ld\n", rec(m, ans));
  }

  return 0;
}