【leetcode】1512. Number of Good Pairs

题目如下：

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:

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 

Constraints:

• 1 <= nums.length <= 100
• 1 <= nums[i] <= 100

解题思路：送分题。

代码如下：

class Solution(object):
    def numIdenticalPairs(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        res = 0
        for i in range(len(nums)):
            for j in range(i+1,len(nums)):
                if nums[i] == nums[j]:
                    res += 1
        return res