原题https://leetcode.com/problems/median-of-two-sorted-arrays/

内容为两个排序好的非空列表，求这两个表之间的中位数。难点在对时间复杂度有要求。

class Solution:
    def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:
        lis=nums1+nums2
        lis=sorted(lis)
        return lis[int(len(lis)/2)] if (len(lis)%2)!=0 else (lis[int(len(lis)/2)-1]+lis[int(len(lis)/2)])/2
        

原题https://leetcode.com/problems/two-sum/

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        st={}
        ac=[]
        for i,val in enumerate(nums):
            if val in st:
                ac.append(st[val])
                ac.append(i)
                return ac
            else:
                st[target-val]=i
            
        
            
        

原题https://leetcode.com/problems/longest-substring-without-repeating-characters/submissions/

最长子窜

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        st = {}
        i=0
        max1 = 0
        for j in range(len(s)):
            if s[j] in st:
                i = max(st[s[j]], i)#起始位置换到原始重复位置的后一位，如ab遇到a就变成ba去继续遇下一位
            max1 = max(max1, j - i + 1)
            st[s[j]] = j+1
        return max1

原题https://leetcode.com/problems/longest-substring-without-repeating-characters/submissions/

经典题 最长子窜长度

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        if s=="":
            return 0
        
        max1 = 1
        for i in range(0,len(s)-1):
            b=[]
            b.append(s[i])
            for j in range(i+1,len(s)) :
            
                if s[j] not in b:
                    b.append(s[j])
                else:
                    max1=(len(b) if len(b)>max1 else max1)#遇到重复立马打断循环 计数
                    break
                #print(b)
            max1=(len(b) if len(b)>max1 else max1)#没有遇到任何重复 计数
            
        
        
        return max1
        
        

原题https://leetcode.com/problems/two-sum/submissions/

题目内容 寻找列表两个数之和为指定数字的位置

 

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
        b=[]
        for i,val in enumerate(nums):
            tmp=nums[i+1:]
            if (target-val) in tmp:
                b.append(i)
                b.append(i+1+tmp.index(target-val))
        return b

题目：https://leetcode.com/problems/add-two-numbers/

两个单链表相加，输出一个单链表

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def backNode(self,node:ListNode)->int:
        back =0
        if node is None:
            return back
        cur = node
        cnt=-1
        while cur is not None:
            cnt+=1
            back+=cur.val*(10**cnt)
            cur = cur.next
        return back
    
    def genNode(self,l1:list)->ListNode:
        
        head = ListNode(l1[0])
        p=head
        
        for i in range(1,len(l1)):
            
            p.next=ListNode(l1[i])
            p=p.next
        return head
            
            
    
    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
        print (self.backNode(l1))
        print (self.backNode(l2))
        sum=self.backNode(l1)+self.backNode(l2)
        list1=[int(x) for x in str(sum)]
        print (list1[::-1])
        list2=list1[::-1]
        
        
        return self.genNode(list2)

之前玩各种固件，所以刷了很多u盘启动器，现在想恢复还得折腾下，下面记录个比较简单的方式。

1.打开cmd

2.输入 diskpart #进入磁盘管理工具

3.继续输入 lis dis #查看当前磁盘分区

4.输入 sel dis 1 #选择要恢复的磁盘

5.输入 clean #清除磁盘

6.输入 create partition primary #新建主分区

7.直接在我的电脑里格式化就可以正常使用了

适合将iso或者img镜像写入到u盘等介质中。

1.diskutil list #查看当前磁盘分区

2.diskutil unmountDisk /dev/disk2 #卸载要写的介质

3.sudo dd if=lubuntu-16.04.dmg of=/dev/rdisk2 bs=4m #快速写入镜像

4.iostat -w 2 #新开一个终端，查看第3步的镜像写入进度

5.diskutil eject /dev/disk2 #弹出介质