1_two_sum.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
Author: wangluyu
Date: 2020/1/3
"""
from typing import List


class Solution:
    """
    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.
    Example:
    Given nums = [2, 7, 11, 15], target = 9,
    Because nums[0] + nums[1] = 2 + 7 = 9,
    return [0, 1].
    给定一个整数数组 nums 和一个目标值 target，请你在该数组中找出和为目标值的那 两个 整数，并返回他们的数组下标。
    你可以假设每种输入只会对应一个答案。但是，你不能重复利用这个数组中同样的元素。
    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]
    """

    def twoSum(self, nums: List[int], target: int) -> List[int]:
        for i, v1 in enumerate(nums):
            v2 = target - v1
            if v2 in nums[i+1:]:
                return [i, nums.index(v2, i + 1)]


if __name__ == '__main__':
    _s = Solution()
    print(_s.twoSum(nums=[2,7,11,15], target=9)) # [0,1]
    print(_s.twoSum(nums=[3,2,4], target=6)) # [1,2]