You are given a 0-indexed, strictly increasing integer array nums and a positive integer diff. A triplet (i, j, k) is an arithmetic triplet if the following conditions are met:
i < j < k,nums[j] - nums[i] == diff, andnums[k] - nums[j] == diff.Return the number of unique arithmetic triplets.
Example 1:
Input: nums = [0,1,4,6,7,10], diff = 3 Output: 2 Explanation: (1, 2, 4) is an arithmetic triplet because both 7 - 4 == 3 and 4 - 1 == 3. (2, 4, 5) is an arithmetic triplet because both 10 - 7 == 3 and 7 - 4 == 3.
Example 2:
Input: nums = [4,5,6,7,8,9], diff = 2 Output: 2 Explanation: (0, 2, 4) is an arithmetic triplet because both 8 - 6 == 2 and 6 - 4 == 2. (1, 3, 5) is an arithmetic triplet because both 9 - 7 == 2 and 7 - 5 == 2.
Constraints:
3 <= nums.length <= 2000 <= nums[i] <= 2001 <= diff <= 50nums is strictly increasing.This approach focuses on solving the problem iteratively, using a loop to process elements step by step. Choose this method if the problem is naturally sequential or requires processing each element in turn.
The C solution processes each element of the input array in a simple for-loop, demonstrating an iterative approach.
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Time Complexity: O(n), where n is the number of elements in the array.
Space Complexity: O(1), as we are using only a constant amount of extra space.
This approach leverages recursion to solve the problem. It is particularly useful when the problem can be broken down into smaller subproblems of the same nature.
A recursive C solution where the function prints the current element and calls itself for the next index.
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Java
Python
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Time Complexity: O(n)
Space Complexity: O(n), due to recursion stack space.
| Approach | Complexity |
|---|---|
| Approach 1: Iterative Solution | Time Complexity: O(n), where n is the number of elements in the array. |
| Approach 2: Recursive Solution | Time Complexity: O(n) |
Leetcode 2367. Number of Arithmetic Triplets | Weekly Contest 305. Easy • Code with Alisha • 5,181 views views
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