第一题:两数之和
答案:
class Solution(object): def twoSum(self, nums, target): """ :type nums: List[int] :type target: int :rtype: List[int] """ num_map = {} for i,num in enumerate(nums): complement = target - num if complement in num_map: return [num_map[complement],i] num_map[num] = i return []思路:
什么时候想到用哈希法做映射:
每当我们要判断这个元素是否出现过