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leetcode 1. Two Sum

时间:2018-06-13 00:15:13      阅读:196      评论:0      收藏:0      [点我收藏+]

标签:NPU   each   two sum   may   sort   +=   input   python   sum   

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].


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

另外就是sort后的解法:

class Solution:
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """        
        nums2 = [(i,n) for i,n in enumerate(nums)]
        nums2.sort(key=lambda x: x[1])
        i,j = 0, len(nums2)-1
        while i<j:
            if nums2[i][1] + nums2[j][1] == target:
                return [nums2[i][0], nums2[j][0]]
            elif nums2[i][1] + nums2[j][1] > target:
                j -= 1
            else:
                i += 1

 如果是二分查找的two sum,我就不写了。

leetcode 1. Two Sum

标签:NPU   each   two sum   may   sort   +=   input   python   sum   

原文地址:https://www.cnblogs.com/bonelee/p/9175540.html

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