两数之和

题目
# 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(object):
    def twoSum(self, nums, target):
        rec_dict = {}
        for i in range(len(nums)):
            if nums[i] in rec_dict:
                return [rec_dict[nums[i]],i]
            else:
                rec_dict[target-nums[i]] = i

class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        d = {}
        for i,m in enumerate(nums):
            d[m] = i
        
        for i,m in enumerate(nums):
            n = target-m
            if n in d and (i != d[n]):
                return [i,d[n]]
        

class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        count = 0
        for i1,i in enumerate(nums[:-1]):
            count+=1
            for i2,j in enumerate(nums[nums.index(i)+1:]):
                if i+j == target:
                    return [i1,i2+count]