<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[yifeng113的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/yifeng113</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; yifeng113]]></copyright><item><title><![CDATA[力扣29——加油站]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/105175679</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/105175679</guid><author>yifeng113</author><pubDate>Sun, 29 Mar 2020 11:32:38 +0800</pubDate><description><![CDATA[class Solution:
    def canCompleteCircuit(self, gas: List[int], cost: List[int]) -&gt; int:
        n=len(gas)
        for i in range(n):
            if gas[i]&lt;cost[i]:
                continue
  ...]]></description><category></category></item><item><title><![CDATA[力扣18——跳跃游戏]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/105159191</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/105159191</guid><author>yifeng113</author><pubDate>Sat, 28 Mar 2020 12:38:33 +0800</pubDate><description><![CDATA[class Solution:
    def canJump(self, nums: List[int]) -&gt; bool:
        n=len(nums)-2
        m=len(nums)-1
        while n&gt;=0:
            if nums[n]+n&gt;=m:
                m=n
            n-...]]></description><category></category></item><item><title><![CDATA[力扣27——分发饼干]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/105138780</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/105138780</guid><author>yifeng113</author><pubDate>Fri, 27 Mar 2020 12:44:30 +0800</pubDate><description><![CDATA[先对量列表排序，然后设置双指针，状态转移为sj&gt;=gi,则i，j加1并人数加1，否则i+1，不加人数。边界加0：
class Solution:
    def findContentChildren(self, g: List[int], s: List[int]) -&gt; int:
        i=j=0
        g.sort()
        s.sort()
   ...]]></description><category></category></item><item><title><![CDATA[力扣26——判断子序列]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/105124074</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/105124074</guid><author>yifeng113</author><pubDate>Thu, 26 Mar 2020 17:44:31 +0800</pubDate><description><![CDATA[子问题是s每往后移动一个单位，是否还是t的子序列：
class Solution:
    def isSubsequence(self, s: str, t: str) -&gt; bool:
        def d(i:int,s:str,t:str):
            if i==len(s):
                return True
            if...]]></description><category></category></item><item><title><![CDATA[力扣第21天——二叉树最大深度]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/105003353</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/105003353</guid><author>yifeng113</author><pubDate>Sat, 21 Mar 2020 08:24:15 +0800</pubDate><description><![CDATA[小小用一下dp思想，定义dp函数含义为目标节点处的最大深度，base case为叶子节点返回1，其他节点返回左右子节点最大函数值：
class Solution:
    def maxDepth(self, root: TreeNode) -&gt; int:
        if root==None:
            return 0
        t=root
        i...]]></description><category></category></item><item><title><![CDATA[力扣第20天——对称二叉树]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104982363</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104982363</guid><author>yifeng113</author><pubDate>Fri, 20 Mar 2020 08:56:21 +0800</pubDate><description><![CDATA[递归，递归函数定义是判断两节点是否构成镜像：
class Solution:
    def isSymmetric(self, root: TreeNode) -&gt; bool:
        p=root
        q=root
        def Symmetric(t1,t2):
            if t1==None and t2==None:
         ...]]></description><category></category></item><item><title><![CDATA[力扣第18天——相同的树]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104975269</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104975269</guid><author>yifeng113</author><pubDate>Thu, 19 Mar 2020 20:04:55 +0800</pubDate><description><![CDATA[递归，四种情况：
1.两节点都为空，True
2.只有一个为空，False
3.val不等，False
4.val相等，判断左右子节点
class Solution:
    def isSameTree(self, p: TreeNode, q: TreeNode) -&gt; bool:
        if p==None and q==None:
            return Tr...]]></description><category></category></item><item><title><![CDATA[力扣第18天——正则表达式]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104942090</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104942090</guid><author>yifeng113</author><pubDate>Wed, 18 Mar 2020 12:37:08 +0800</pubDate><description><![CDATA[看了大佬思路的暴力递归，还有待优化：
class Solution:
    def isMatch(self, s: str, p: str) -&gt; bool:
        def ism(s,p):
            if p=='':
                if s=='':
                    return True
             ...]]></description><category></category></item><item><title><![CDATA[力扣第17天——最长回文子串]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104918795</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104918795</guid><author>yifeng113</author><pubDate>Tue, 17 Mar 2020 12:05:49 +0800</pubDate><description><![CDATA[参考大佬的思路，对暴力遍历做优化：
class Solution:
    def longestPalindrome(self, s: str) -&gt; str:
        l=len(s)
        if l==1 or l==0:
            return s
        max_len=1
        start=0
        dp=[[False...]]></description><category></category></item><item><title><![CDATA[力扣第16天——无重复字符的最长子串]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104896190</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104896190</guid><author>yifeng113</author><pubDate>Mon, 16 Mar 2020 12:02:14 +0800</pubDate><description><![CDATA[来个菜鸟的做法：
class Solution:
    def lengthOfLongestSubstring(self, s: str) -&gt; int:
        if s=='':
            return 0
        dp=[1]*len(s)
        for i in range(1,len(s)):
            j=i-1
    ...]]></description><category></category></item><item><title><![CDATA[力扣第15天——有效的括号]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104873806</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104873806</guid><author>yifeng113</author><pubDate>Sun, 15 Mar 2020 09:58:50 +0800</pubDate><description><![CDATA[class Solution:
    def isValid(self, s: str) -&gt; bool:
        a=[0]
        for i in s:
            if i=='[' or i=='(' or i=='{':
                a.append(i)
            if i==')':
              ...]]></description><category></category></item><item><title><![CDATA[力扣第14天——最长公共前缀]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104858305</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104858305</guid><author>yifeng113</author><pubDate>Sat, 14 Mar 2020 12:30:14 +0800</pubDate><description><![CDATA[选取第一个元素一次和后续元素比较，如find方法返回值部位0，则去除尾项，直至返回0：
class Solution:
    def longestCommonPrefix(self, strs: List[str]) -&gt; str:
        if strs==[]:
            return ""
        a=strs[0]
        for i in ...]]></description><category></category></item><item><title><![CDATA[力扣第13天——罗马数字转整数]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104838377</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104838377</guid><author>yifeng113</author><pubDate>Fri, 13 Mar 2020 12:28:43 +0800</pubDate><description><![CDATA[考虑三种特殊情况即可:
class Solution:
    def romanToInt(self, s: str) -&gt; int:
        tap=dict([('I',1),('V',5),('X',10),('L',50),('C',100),('D',500),('M',1000)])
        sum=0
        for i in range(len(s)...]]></description><category></category></item><item><title><![CDATA[力扣第12天——合并k个排序链表]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104819291</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104819291</guid><author>yifeng113</author><pubDate>Thu, 12 Mar 2020 14:59:07 +0800</pubDate><description><![CDATA[暴力法
class Solution:
    def mergeKLists(self, lists: List[ListNode]) -&gt; ListNode:
        m=[]
        head=point=ListNode(0)
        for i in lists:
            while i:
                m.append(i...]]></description><category></category></item><item><title><![CDATA[力扣第11天——删除链表第N个节点]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104789343</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104789343</guid><author>yifeng113</author><pubDate>Wed, 11 Mar 2020 09:10:02 +0800</pubDate><description><![CDATA[两遍遍历：
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def removeNthFromEnd(self, head: ListNo...]]></description><category></category></item><item><title><![CDATA[力扣第10天——两数相加]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104780319</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104780319</guid><author>yifeng113</author><pubDate>Tue, 10 Mar 2020 18:33:45 +0800</pubDate><description><![CDATA[class Solution:
    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -&gt; ListNode:
        def get_nums(l:ListNode):
            if not l:
                return 0
            return l.val+get_nu...]]></description><category></category></item><item><title><![CDATA[力扣第九天——环形链表]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104746483</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104746483</guid><author>yifeng113</author><pubDate>Mon, 09 Mar 2020 09:56:49 +0800</pubDate><description><![CDATA[# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def hasCycle(self, head: ListNode) -&gt; bool...]]></description><category></category></item><item><title><![CDATA[力扣第8天——删除链表中重复元素]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104729638</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104729638</guid><author>yifeng113</author><pubDate>Sun, 08 Mar 2020 11:36:05 +0800</pubDate><description><![CDATA[此题设置双指针遍历链表，当前指针指向None叫停即可：
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def deleteDuplica...]]></description><category></category></item><item><title><![CDATA[力扣第七天——合并两个有序链表]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104714198</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104714198</guid><author>yifeng113</author><pubDate>Sat, 07 Mar 2020 14:17:15 +0800</pubDate><description><![CDATA[两个输入链表都是有序的，因此先创建一个val维-1的链表头部，然后根据l1和l2的大小关系上下横跳即可：
class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -&gt; ListNode:
        prehead=ListNode(-1)
        pr=prehead
        whi...]]></description><category></category></item><item><title><![CDATA[力扣第五天——最接近三数之和]]></title><link>https://blog.youkuaiyun.com/yifeng113/article/details/104683324</link><guid>https://blog.youkuaiyun.com/yifeng113/article/details/104683324</guid><author>yifeng113</author><pubDate>Thu, 05 Mar 2020 21:14:04 +0800</pubDate><description><![CDATA[class Solution(object):
    def threeSumClosest(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        nums = sorted(nums)
   ...]]></description><category></category></item></channel></rss>