Problem p02609 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#include <chrono>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace std::chrono;
using namespace __gnu_pbds;
#define fastio                                                                 \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define fi first
#define se second
#define int long long
#define pb push_back
#define emp emplace_back
#define vv(x) vector<x>
#define mp(x, y) map<x, y>
#define dq(x) deque<x>
#define pql(x) priority_queue<x>
#define pqs(x) priority_queue<x, vv(x), greater<x>>
#define M 1000000007
#define forf(i, a, b) for (int i = a; i < b; i++)
#define it(x) x::iterator
#define ll long long
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#define time__(d)                                                              \
  for (long blockTime = 0;                                                     \
       (blockTime == 0 ? (blockTime = clock()) != 0 : false);                  \
       debug("%s time : %.4fs", d,                                             \
             (double)(clock() - blockTime) / CLOCKS_PER_SEC))
#define vii vector<int>
#define big 3e18
#define sm -2e9
#define mkr make_pair
#define vpi vector<pair<int, int>>
#define pii pair<int, int>
#define rng 500005
#define sz(x) (int)x.size()
#define rv(x) reverse(x.begin(), x.end())
#define out(x) cout << x.fi << " " << x.se << endl;

// #define ordered_set tree<pii, null_type,less<pii>,
// rb_tree_tag,tree_order_statistics_node_update>

void pr_init() {

#ifndef ONLINE_JUDGE
  freopen("gin.txt", "r", stdin);
  freopen("gout.txt", "w", stdout);

#endif
}

int raise(int a, int b, int m) {
  int an = 1;

  while (b > 0) {
    if (b % 2 != 0)
      an = ((an % m) * (a % m)) % m;
    b /= 2;
    a = ((a % m) * (a % m)) % m;
  }
  return an;
}
int dp[2];

int process(int a) {
  int an = 0;
  while (a > 0) {
    int cn = 0;
    for (int i = 0; i <= 32; i++) {
      if ((a >> i) & 1)
        cn++;
    }
    an++;
    a %= cn;
  }
  return an;
}
void solve() {

  int n;
  cin >> n;

  string s;
  cin >> s;

  int cn = 0;

  forf(i, 0, n) {
    if (s[i] == '1')
      cn++;
  }

  forf(j, 0, n) {
    if (cn > 1)
      dp[0] += (raise(2, n - j - 1, cn - 1) * (s[j] - '0')) % (cn - 1),
          dp[0] %= (cn - 1);
    if (cn < n)
      dp[1] += (raise(2, n - j - 1, cn + 1) * (s[j] - '0')) % (cn + 1),
          dp[1] %= (cn + 1);
  }

  forf(i, 0, n) {
    if (s[i] == '0') {
      int an = dp[1];
      an = an + raise(2, n - i - 1, cn + 1);
      an %= cn + 1;

      cout << process(an) + 1 << "\n";

    } else {
      int an = dp[0];
      an = an - raise(2, n - i - 1, cn - 1) + cn - 1;
      an %= cn - 1;

      cout << process(an) + 1 << "\n";
    }
  }
}

int32_t main() {
  pr_init();
  fastio;

  auto start = high_resolution_clock::now();

  solve();
  auto stop = high_resolution_clock::now();
  auto duration = duration_cast<microseconds>(stop - start);
  // cout << "Time taken by function: "
  //       << duration.count() << " microseconds" << endl;
}


Fixed submission:
#include <bits/stdc++.h>
#include <chrono>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace std::chrono;
using namespace __gnu_pbds;
#define fastio                                                                 \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0)
#define fi first
#define se second
#define int long long
#define pb push_back
#define emp emplace_back
#define vv(x) vector<x>
#define mp(x, y) map<x, y>
#define dq(x) deque<x>
#define pql(x) priority_queue<x>
#define pqs(x) priority_queue<x, vv(x), greater<x>>
#define M 1000000007
#define forf(i, a, b) for (int i = a; i < b; i++)
#define it(x) x::iterator
#define ll long long
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#define time__(d)                                                              \
  for (long blockTime = 0;                                                     \
       (blockTime == 0 ? (blockTime = clock()) != 0 : false);                  \
       debug("%s time : %.4fs", d,                                             \
             (double)(clock() - blockTime) / CLOCKS_PER_SEC))
#define vii vector<int>
#define big 3e18
#define sm -2e9
#define mkr make_pair
#define vpi vector<pair<int, int>>
#define pii pair<int, int>
#define rng 500005
#define sz(x) (int)x.size()
#define rv(x) reverse(x.begin(), x.end())
#define out(x) cout << x.fi << " " << x.se << endl;

// #define ordered_set tree<pii, null_type,less<pii>,
// rb_tree_tag,tree_order_statistics_node_update>

void pr_init() {

#ifndef ONLINE_JUDGE
  freopen("gin.txt", "r", stdin);
  freopen("gout.txt", "w", stdout);

#endif
}

int raise(int a, int b, int m) {
  int an = 1;

  while (b > 0) {
    if (b % 2 != 0)
      an = ((an % m) * (a % m)) % m;
    b /= 2;
    a = ((a % m) * (a % m)) % m;
  }
  return an;
}
int dp[2];

int process(int a) {
  int an = 0;
  while (a > 0) {
    int cn = 0;
    for (int i = 0; i <= 32; i++) {
      if ((a >> i) & 1)
        cn++;
    }
    an++;
    a %= cn;
  }
  return an;
}
void solve() {

  int n;
  cin >> n;

  string s;
  cin >> s;

  int cn = 0;

  forf(i, 0, n) {
    if (s[i] == '1')
      cn++;
  }

  forf(j, 0, n) {
    if (cn > 1)
      dp[0] += (raise(2, n - j - 1, cn - 1) * (s[j] - '0')) % (cn - 1),
          dp[0] %= (cn - 1);
    if (cn < n)
      dp[1] += (raise(2, n - j - 1, cn + 1) * (s[j] - '0')) % (cn + 1),
          dp[1] %= (cn + 1);
  }

  forf(i, 0, n) {
    if (s[i] == '0') {
      int an = dp[1];
      an = an + raise(2, n - i - 1, cn + 1);
      an %= cn + 1;

      cout << process(an) + 1 << "\n";

    } else {
      if (cn == 1) {
        cout << "0\n";
        continue;
      }
      int an = dp[0];
      an = an - raise(2, n - i - 1, cn - 1) + cn - 1;
      an %= cn - 1;

      cout << process(an) + 1 << "\n";
    }
  }
}

int32_t main() {
  pr_init();
  fastio;

  auto start = high_resolution_clock::now();

  solve();
  auto stop = high_resolution_clock::now();
  auto duration = duration_cast<microseconds>(stop - start);
  // cout << "Time taken by function: "
  //       << duration.count() << " microseconds" << endl;
}