[LeetCode]#2367. Number of Arithmetic Triplets
1 min readNov 22, 2022
Environment: Python 3.8
Key technique: in
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.
Analysis:
- Check nums[i]+diff and nums[i]+2*diff in nums
Solution:
class Solution:
def arithmeticTriplets(self, nums, diff):
ans=0
for i in range(len(nums)):
if nums[i]+diff in nums and nums[i]+diff*2 in nums:
ans+=1
return ans
Submissions:
Reference: