#1512

Number of Good Pairs

newbie · 100 · lc easy +12 · verified · 89.8% accepted · 5,852 likes · top 99%

Description

Given an integer array nums, count the pairs (i, j) where i < j and nums[i] == nums[j]. Return that count.

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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