Given an array of integers nums, return the number of good pairs.
A pair (i, j) is called good if nums[i] == nums[j] and i < j.
+
Example 1:
+ +Input: nums = [1,2,3,1,1,3] +Output: 4 +Explanation: There are 4 good pairs (0,3), (0,4), (3,4), (2,5) 0-indexed. ++ +
Example 2:
+ +Input: nums = [1,1,1,1] +Output: 6 +Explanation: Each pair in the array are good. ++ +
Example 3:
+ +Input: nums = [1,2,3] +Output: 0 ++ +
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Constraints:
+ +1 <= nums.length <= 1001 <= nums[i] <= 100