leetcode学习笔记(两数之和/排列构建数组/数组串联)

class Solution:
    def twoSum(self, nums, target) :
        lens = len(nums)
        j=-1
        for i in range(lens):
            left = nums[:i]
            if (target - nums[i]) in left:
                j = left.index(target - nums[i])
                break
        if j>=0:
            return [j,i]

class Solution:
    def twoSum(self, nums, target) :
        amap={}
        for i,num in enumerate(nums):
            if amap.get(target - num) is not None:
                return [amap.get(target - num),i]
            amap[num] = i

class Solution:
    def buildArray(self, nums):
        n = len(nums)
        ans = []
        for i in range(n):
            ans.append(nums[nums[i]])
        return ans

class Solution:
    def getConcatenation(self, nums) :
        n = len(nums)
        for i in range(n):
            nums.append(nums[i])
        return nums

class Solution:
    def getConcatenation(self, nums) :
        a = nums
        nums.extend(a)
        return nums