LeetCode in Python-1. Two Sum 兩數之和

題目描述

解法1、切片後查找

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        for i in nums:
            j = target - i
            start_index = nums.index(i)
            next_index = start_index + 1
            temp_nums = nums[next_index:]
            if j in temp_nums:
                return [nums.index(i), next_index + temp_nums.index(j)]

注意返回值index的轉換

解法2、hash字典

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        dict = {}
        for i in range(len(nums)):
            if target - nums[i] not in dict:
                dict[nums[i]] = i
            else:
                return [dict[target-nums[i]], i]

解法3、同2

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        dict = {}
        for i, num in enumerate(nums):
            if target - num in dict:
                return [dict[target-num], i]
            dict[num] = i

藉助枚舉函數，方法同2

出處

1、2、https://www.bilibili.com/video/av45727557