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1534. Count Good Triplets 👎

  • Time: $O(n^3)$
  • Space: $O(1)$
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class Solution {
 public:
  int countGoodTriplets(vector<int>& arr, int a, int b, int c) {
    int ans = 0;
    for (int i = 0; i < arr.size(); ++i)
      for (int j = i + 1; j < arr.size(); ++j)
        for (int k = j + 1; k < arr.size(); ++k)
          if (abs(arr[i] - arr[j]) <= a &&  //
              abs(arr[j] - arr[k]) <= b &&  //
              abs(arr[i] - arr[k]) <= c)
            ++ans;
    return ans;
  }
};

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class Solution {
  public int countGoodTriplets(int[] arr, int a, int b, int c) {
    int ans = 0;
    for (int i = 0; i < arr.length; ++i)
      for (int j = i + 1; j < arr.length; ++j)
        for (int k = j + 1; k < arr.length; ++k)
          if (Math.abs(arr[i] - arr[j]) <= a && //
              Math.abs(arr[j] - arr[k]) <= b && //
              Math.abs(arr[i] - arr[k]) <= c)
            ++ans;
    return ans;
  }
}

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class Solution:
  def countGoodTriplets(self, arr: list[int], a: int, b: int, c: int) -> int:
    return sum(abs(arr[i] - arr[j]) <= a and
               abs(arr[j] - arr[k]) <= b and
               abs(arr[i] - arr[k]) <= c
               for i in range(len(arr))
               for j in range(i + 1, len(arr))
               for k in range(j + 1, len(arr)))