Leetcode - Number of Good Pairs Solution
Poor Man
- Published
- Updated
- Reading time
- 1 min read
- Length
- 117 words
Given an array of integers nums.
A pair (i,j) is called good if nums[i] == nums[j] and i < j.
Return the number of good pairs.
Example 1:
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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:
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Input: nums = [1,1,1,1]
Output: 6
Explanation: Each pair in the array are good.Example 3:
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Input: nums = [1,2,3]
Output: 0Constraints:
1 <= nums.length <= 1001 <= nums[i] <= 100
Solution in Python#
Python
from collections import Counter
class Solution:
def numIdenticalPairs(self, nums: List[int]) -> int:
return sum((n)*(n-1)//2 for n in Counter(nums).values())