LeetCode-001

# 给定一个整数数组和一个目标值，找出数组中和为目标值的两个数。
# 你可以假设每个输入只对应一种答案，且同样的元素不能被重复利用。
# 示例:
# 给定 nums = [2, 7, 11, 15], target = 9
# 因为 nums[0] + nums[1] = 2 + 7 = 9
# 所以返回 [0, 1]

class Solution:
    # 暴力超时
    # def twoSum(self, nums, target):
    #     """
    #     :type nums: List[int]
    #     :type target: int
    #     :rtype: List[int]
    #     """
    #     for i in range(len(nums)):
    #         for j in range(len(nums)):
    #             if i!=j and nums[i]+nums[j]==target :
    #                 return [i,j]

    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        dict = {}
        lens = len(nums)
        for i in range(lens):
            if target - nums[i] in dict:
                return [dict[target - nums[i]],i]
            else:
                dict[nums[i]] = i