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

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define int long long
#define all(a) (a).begin(), (a).end()
using namespace __gnu_pbds;
using namespace std;

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_set;

#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \\
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

inline int val(int a, int b, int c) {
  return a * a + b * b + c * c + a * b + b * c + a * c;
}

int fun(int n) {
  int cnt = 0;
  for (int i = 1; i * i <= n; i++) {
    for (int j = 1; j * j + i * i + j * i <= n; j++) {
      for (int k = 1; val(i, j, k) <= n; k++) {
        if (val(i, j, k) == n)
          cnt++;
      }
    }
  }
  return cnt;
}

signed main() {
  ios_base::sync_with_stdio(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cout << fun(i) << endl;
  }
  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define int long long
#define all(a) (a).begin(), (a).end()
using namespace __gnu_pbds;
using namespace std;

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_set;

#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                 \\
  sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(    \\
            c i) {
sim > struct rge {
  c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef LOCAL
  ~debug() { cerr << endl; }
  eni(!=) cerr << boolalpha << i;
  ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
    *this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
#else
  sim dor(const c &) { ris; }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

inline int val(int a, int b, int c) {
  return a * a + b * b + c * c + a * b + b * c + a * c;
}

int fun(int n) {
  int cnt = 0;
  for (int i = 1; i * i <= n; i++) {
    for (int j = 1; j * j <= n; j++) {
      for (int k = 1; k * k <= n; k++) {
        if (val(i, j, k) == n) {
          cnt++;
        }
      }
    }
  }
  return cnt;
}

signed main() {
  ios_base::sync_with_stdio(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cout << fun(i) << endl;
  }
  return 0;
}