1. Two Sum

問題

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, and you may not use the same element twice.

給定一個整數數組,返回兩個數的指數,他們加起來是一個具體的目標。你可能認爲每一個輸入一個解決方案,你可能不會使用相同的元素兩次。

Example:

Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

過程

• 先將數組排序

• 而後遍歷數組，找到一個比他小的數

• 肯定另外一個數的位置，若是不存在，繼續尋找

代碼

class Solution:
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        b = sorted(nums)
        for i in b:
            o = target - i
            if o not in nums:
                continue
            i_index = nums.index(i)
            for idex, item in enumerate(nums):
                if item == o and idex != i_index:
                    return sorted([i_index, idex])