Problem p02608 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define MV 200001
#define LMV 21
#define ff first
#define ss second
#define pb push_back
#define eb emplace_back
#define emp emplace
#define mp make_pair
#define ins insert
#define sz(x) (int)x.size()
#define whoami(args...)                                                        \\
  {                                                                            \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    whi(_it, args);                                                            \\
  }

void whi(istream_iterator<string> it) { cerr << "\\n"; }

template <typename T, typename... Args>
void whi(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " " << a << " ";
  whi(++it, args...);
}

void FLASH() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
void SETF() {
  cout.ios_base::setf(ios_base::fixed);
  cerr.ios_base::setf(ios_base::fixed);
}
void UNSETF() {
  cout.ios_base::unsetf(ios_base::fixed);
  cerr.ios_base::unsetf(ios_base::fixed);
}

typedef long long ll;
typedef long double ld;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef pair<PII, int> PPII;
typedef pair<PLL, ll> PPLL;
typedef map<int, int> MII;

const int MOD = 1000000007;
const ll INF = 4e18;

template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,
                              tree_order_statistics_node_update>;

struct h_llint {
  static uint64_t
  splitmix64(uint64_t x) { // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};

struct h_pair {
  size_t operator()(const PLL &x) const {
    return hash<ll>()(((ll)x.ff) ^ (((ll)x.ss) << 32));
  }
};

typedef map<ll, ll> MLL;
typedef map<PII, int> MPII;
typedef map<PLL, ll> MPLL;
typedef set<int> SI;
typedef set<ll> SL;
// ordered_set = order_of_key(.)
// ordered_set = find_by_order(.)
typedef ordered_set<int> OSI;
typedef ordered_set<ll> OSL;
typedef ordered_multiset<int> MOSI;
typedef ordered_multiset<ll> MOSL;
typedef unordered_map<ll, int, h_llint> UMLI;
typedef unordered_map<ll, ll, h_llint> UMLL;
typedef unordered_map<PLL, int, h_pair> UMPI;
typedef unordered_map<PLL, ll, h_pair> UMPL;

int ar[MV];
ll arr[MV];

void solve(int T) {
  int n;
  cin >> n;
  for (int i = 2; i * i <= 2 * n; i++) {
    for (int j = 2; j * j <= 2 * n; j++) {
      for (int k = 2; k * k <= 2 * n; k++) {
        int a = i * i;
        int b = j * j;
        int c = k * k;
        if (!((a + b + c) & 1) && (i + j - k > 0) && !((i + j - k) & 1) &&
            (i - j + k > 0) && !((i - j + k) & 1) && (-i + j + k > 0) &&
            !((-i + j + k) & 1))
          ar[(a + b + c) >> 1]++;
      }
    }
  }
  for (int i = 1; i <= n; i++)
    cout << ar[i] << "\\n";
  return;
}

int main(void) {
  FLASH();
  // freopen("cowjog.in", "r", stdin);
  // freopen("cowjog.out", "w", stdout);
  int T;
  T = 1;

#ifndef ONLINE_JUDGE
  time_t time_t1, time_t2;
  time_t1 = clock();
#endif

  // cin>>T;
  while (T--)
    solve(T);

#ifndef ONLINE_JUDGE
  time_t2 = clock();
  SETF();
  cerr << "Time taken: " << setprecision(7)
       << (time_t2 - time_t1) / (double)CLOCKS_PER_SEC << "\\n";
  UNSETF();
#endif

  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define MV 200001
#define LMV 21
#define ff first
#define ss second
#define pb push_back
#define eb emplace_back
#define emp emplace
#define mp make_pair
#define ins insert
#define sz(x) (int)x.size()
#define whoami(args...)                                                        \\
  {                                                                            \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    whi(_it, args);                                                            \\
  }

void whi(istream_iterator<string> it) { cerr << "\\n"; }

template <typename T, typename... Args>
void whi(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " " << a << " ";
  whi(++it, args...);
}

void FLASH() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
}
void SETF() {
  cout.ios_base::setf(ios_base::fixed);
  cerr.ios_base::setf(ios_base::fixed);
}
void UNSETF() {
  cout.ios_base::unsetf(ios_base::fixed);
  cerr.ios_base::unsetf(ios_base::fixed);
}

typedef long long ll;
typedef long double ld;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef pair<PII, int> PPII;
typedef pair<PLL, ll> PPLL;
typedef map<int, int> MII;

const int MOD = 1000000007;
const ll INF = 4e18;

template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,
                              tree_order_statistics_node_update>;

struct h_llint {
  static uint64_t
  splitmix64(uint64_t x) { // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};

struct h_pair {
  size_t operator()(const PLL &x) const {
    return hash<ll>()(((ll)x.ff) ^ (((ll)x.ss) << 32));
  }
};

typedef map<ll, ll> MLL;
typedef map<PII, int> MPII;
typedef map<PLL, ll> MPLL;
typedef set<int> SI;
typedef set<ll> SL;
// ordered_set = order_of_key(.)
// ordered_set = find_by_order(.)
typedef ordered_set<int> OSI;
typedef ordered_set<ll> OSL;
typedef ordered_multiset<int> MOSI;
typedef ordered_multiset<ll> MOSL;
typedef unordered_map<ll, int, h_llint> UMLI;
typedef unordered_map<ll, ll, h_llint> UMLL;
typedef unordered_map<PLL, int, h_pair> UMPI;
typedef unordered_map<PLL, ll, h_pair> UMPL;

int ar[MV];
ll arr[MV];

int bs2(int x) {
  int lo = 1;
  int hi = 10000;
  while (lo < hi) {
    int mid = lo + (hi - lo + 1) / 2;
    if (mid * mid <= x)
      lo = mid;
    else
      hi = mid - 1;
  }
  return lo;
}

void solve(int T) {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int nn = 0;
    for (int j = 2; j * j <= 2 * i; j++) {
      for (int k = 2; k * k <= (2 * i - j * j); k++) {
        int a = j * j;
        int b = k * k;
        int c = 2 * i - j * j - k * k;
        int f = bs2(c);
        if ((c > 1) && (f * f == c) && (a + b - c > 0) && !((a + b - c) & 1) &&
            (a - b + c > 0) && !((a - b + c) & 1) && (-a + b + c > 0) &&
            !((-a + b + c) & 1))
          nn++;
      }
    }
    cout << nn << "\\n";
  }
  return;
}

int main(void) {
  FLASH();
  // freopen("cowjog.in", "r", stdin);
  // freopen("cowjog.out", "w", stdout);
  int T;
  T = 1;

#ifndef ONLINE_JUDGE
  time_t time_t1, time_t2;
  time_t1 = clock();
#endif

  // cin>>T;
  while (T--)
    solve(T);

#ifndef ONLINE_JUDGE
  time_t2 = clock();
  SETF();
  cerr << "Time taken: " << setprecision(7)
       << (time_t2 - time_t1) / (double)CLOCKS_PER_SEC << "\\n";
  UNSETF();
#endif

  return 0;
}