两个数组的交集 II

解法是使用字典保存nums1和其计数，再遍历nums2即可

class Solution:
    def intersect(self, nums1: List[int], nums2: List[int]) -> List[int]:
        v1 = {}
        for n1 in nums1:
            try:
                v1[n1] += 1
            except:
                v1[n1] = 1
        result = []       
        for n2 in nums2:
            try:
                v1[n2] -= 1
                result.append(n2)
                if v1[n2] == 0:
                    v1.pop(n2)
            except:
                pass
        
        return result