1_two_sum_version1.py

# Given an array of integers, return indices of the two numbers
# such that they add up to a specific target.
#
# You may assume that each input would have exactly one solution.
#
# Example:
# Given nums = [2, 7, 11, 15], target = 9,
#
# Because nums[0] + nums[1] = 2 + 7 = 9,
# return [0, 1].

# Version1: could run, but not efficient: Time Limit Exceeded.
class Solution:
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        for i in range(0, len(nums)):
            for j in range(i+1, len(nums)):
                if target-nums[i] == nums[j]:
                    return [i,j]