# 1512. Number of Good Pairs """ 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' """ class Solution(object): def numIdenticalPairs(self, nums): cnt = 0 for i in range(len(nums)): for j in range(i + 1, len(nums)): if nums[i] == nums[j]: cnt += 1 return cnt if __name__ == "__main__": obj = Solution() print(obj.numIdenticalPairs([1,2,3,1,1,3])) # expect: 4 print(obj.numIdenticalPairs([1,1,1,1])) # expect: 6 print(obj.numIdenticalPairs([1,2,3])) # expect: 0