LeetCode题解(1577)：数组中某数的平方等于另外两数乘积的组合数量(Python)

题目：​​原题链接​​（中等）

标签：哈希表、数学

解法一：

class Solution:
    def numTriplets(self, nums1: List[int], nums2: List[int]) -> int:
        # 类型1
        ans = 0
        for i in range(len(nums1)):
            n1 = nums1[i] ** 2
            tmp = collections.Counter()
            for n2 in nums2:
                n3 = n1 / n2
                if n3 in tmp:
                    ans += tmp[n3]
                tmp[n2] += 1

        # 类型2
        for i in range(len(nums2)):
            n1 = nums2[i] ** 2
            tmp = collections.Counter()
            for n2 in nums1:
                n3 = n1 / n2
                if n3 in tmp:
                    ans += tmp[n3]
                tmp[n2] += 1

        return ans