Problem p02609 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <complex>
#include <cstring>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for (int i = 0; i < n; ++i)
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define RREP(i, n) for (int i = n - 1; i >= 0; --i)
#define RFOR(i, a, b) for (int i = b - 1; i >= a; --i)

#define all(x) begin(x), end(x)
#define dump(x) cerr << #x << " = " << (x) << endl
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

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

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

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> p) {
  os << p.first << ":" << p.second;
  return os;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[";
  REP(i, SZ(v)) {
    if (i)
      os << ", ";
    os << v[i];
  }
  return os << "]";
}

template <class T1, class T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
  os << "[";
  for (auto it = mp.begin(); it != mp.end(); ++it) {
    if (it != mp.begin()) {
      os << ", ";
    }
    os << *it;
  }
  return os << "]";
}

// edit

ll func(ll val) {
  if (val == 0)
    return 0;
  int nm = __builtin_popcount((unsigned)val);

  ll tmp = func(val % nm) + 1;
  return tmp;
}

ll pow(ll x, ll p, ll m) {
  ll base = x;
  ll ret = 1;

  while (p > 0) {
    if (p % 2) {
      ret = ret * base % m;
    }
    base = base * base % m;
    p >>= 1;
  }

  return ret;
}

void solve() {

  int N;
  string X;
  cin >> N >> X;

  string S = X;
  ll cnt = 0;
  REP(j, N) {
    if (S[j] == '1')
      cnt++;
  }
  ll pcnt = cnt;

  ll mm = 0;
  ll mp = 0;
  REP(j, N) {
    mp *= 2;
    mp += S[j] - '0';
    mp %= cnt + 1;

    if (cnt > 1) {
      mm *= 2;
      mm += S[j] - '0';
      mm %= cnt - 1;
    }
  }

  for (int i = 0; i < N; ++i) {
    if (S[i] == '1') {
      cnt--;
    } else {
      cnt++;
    }
    S[i] ^= 1;

    if (cnt == 0) {
      cout << 0 << endl;
      if (S[i] == '1') {
        cnt--;
      } else {
        cnt++;
      }
      S[i] ^= 1;
      continue;
    }

    if (cnt == 1) {
      cout << 1 << endl;
      if (S[i] == '1') {
        cnt--;
      } else {
        cnt++;
      }
      S[i] ^= 1;
      continue;
    }

    ll val = 0;
    REP(j, N) {
      val *= 2;
      val += S[j] - '0';
      val %= cnt;
    }
    //        cerr << val << endl;

    ll diff = pow(2, N - 1 - i, cnt);

    if (cnt > pcnt) {
      val = mp + diff;
    } else {
      val = mm - diff;
    }
    val %= cnt;
    if (val < 0)
      val += cnt;

    //        cerr << val << endl;

    ll ans = 1 + func(val);
    cout << ans << endl;

    if (S[i] == '1') {
      cnt--;
    } else {
      cnt++;
    }
    S[i] ^= 1;

    //        cerr << "---" << endl;
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  //    std::ifstream in("input.txt");
  //    std::cin.rdbuf(in.rdbuf());

  solve();

  return 0;
}


Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <complex>
#include <cstring>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for (int i = 0; i < n; ++i)
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define RREP(i, n) for (int i = n - 1; i >= 0; --i)
#define RFOR(i, a, b) for (int i = b - 1; i >= a; --i)

#define all(x) begin(x), end(x)
#define dump(x) cerr << #x << " = " << (x) << endl
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;

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

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

template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> p) {
  os << p.first << ":" << p.second;
  return os;
}

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "[";
  REP(i, SZ(v)) {
    if (i)
      os << ", ";
    os << v[i];
  }
  return os << "]";
}

template <class T1, class T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
  os << "[";
  for (auto it = mp.begin(); it != mp.end(); ++it) {
    if (it != mp.begin()) {
      os << ", ";
    }
    os << *it;
  }
  return os << "]";
}

// edit

ll func(ll val, ll m) {
  if (val == 0)
    return 0;
  int nm = __builtin_popcount((unsigned)val);

  ll tmp = func(val % nm, nm) + 1;
  return tmp;
}

void solve() {

  int N;
  string X;
  cin >> N >> X;

  for (int i = 0; i < N; ++i) {
    string S = X;
    S[i] ^= 1;
    ll cnt = 0;
    REP(j, N) {
      if (S[j] == '1')
        cnt++;
    }
    if (cnt == 0) {
      cout << 0 << endl;
      continue;
    }
    if (cnt == 1) {
      cout << 1 << endl;
      continue;
    }

    ll val = 0;
    REP(j, N) {
      val *= 2;
      val %= cnt;
      val += S[j] - '0';
    }

    ll ans = 1 + func(val, cnt);
    cout << ans << endl;
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  //    std::ifstream in("input.txt");
  //    std::cin.rdbuf(in.rdbuf());

  solve();

  return 0;
}