def twoSum(nums, target):
    '''
    @param {List[int]} nums
    @param {int} target
    @return {List[int]}
    '''
    hashMap = {}
    i = 0
    LEN = len(nums)
    while i < LEN:
        # 不能用get判断，因为0和None都会使if不成立
        if target-nums[i] in hashMap:
            # return sorted([i, hashMap.get(target-nums[i])])
            # 字典只有旧的键值，i必然大于字典的任何值
            return i, hashMap.get(target-nums[i])
        else:
            hashMap[nums[i]] = i
            i += 1