Description
You are given a 0-indexed array of positive integers nums
. Find the number of triplets (i, j, k)
that meet the following conditions:
0 <= i < j < k < nums.length
nums[i]
,nums[j]
, andnums[k]
are pairwise distinct.- In other words,
nums[i] != nums[j]
,nums[i] != nums[k]
, andnums[j] != nums[k]
.
- In other words,
Return the number of triplets that meet the conditions.
Example 1:
Input: nums = [4,4,2,4,3] Output: 3 Explanation: The following triplets meet the conditions: - (0, 2, 4) because 4 != 2 != 3 - (1, 2, 4) because 4 != 2 != 3 - (2, 3, 4) because 2 != 4 != 3 Since there are 3 triplets, we return 3. Note that (2, 0, 4) is not a valid triplet because 2 > 0.
Example 2:
Input: nums = [1,1,1,1,1] Output: 0 Explanation: No triplets meet the conditions so we return 0.
Constraints:
3 <= nums.length <= 100
1 <= nums[i] <= 1000
Solution
Python3
class Solution:
def unequalTriplets(self, nums: List[int]) -> int:
N = len(nums)
res = 0
for i in range(N):
for j in range(i + 1, N):
for k in range(j + 1, N):
if nums[i] != nums[j] and nums[i] != nums[k] and nums[j] != nums[k]:
res += 1
return res