随笔分类 - leetcode
摘要：Given a binary tree, return the preorder traversal of its nodes' values. Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [1,2,3] Follow up: Recursive s
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摘要：Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 whic
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摘要：Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. Note: A leaf is a node with no children. Exampl
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摘要：Given a binary tree, flatten it to a linked list in-place. For example, given the following tree: 1 / \ 2 5 / \ \ 3 4 6 The flattened tree should look
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摘要：Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. N
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摘要：Given two binary trees, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally ident
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摘要：Given an unsorted array of integers, find the length of longest increasing subsequence. Example: Input: [10,9,2,5,3,7,101,18] Output: 4 Explanation: T
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摘要：Given two words word1 and word2, find the minimum number of operations required to convert word1 to word2. You have the following 3 operations permitt
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摘要：Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.
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摘要：A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any p
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摘要：Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output:
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摘要：Invert a binary tree. Example: Input: 4 / \ 2 7 / \ / \ 1 3 6 9 Output: 4 / \ 7 2 / \ / \ 9 6 3 1 # Definition for a binary tree node. # class TreeNod
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摘要：Given preorder and inorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example,
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摘要：Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree [3
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摘要："""解题思路：1.荷兰分区问题，我们把数组分成四类：red, white, 未分类, blue。初始的时候都在未分类组里，只要白色指针小于蓝色指针，我们遍历数组2.当白色指针是是红色的时候nums[white]==0,我们交换红色指针，并且两个指针同时+13.当白色指针是白色的时候，位置在正确位置
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摘要：“”“解题思路：遍历数组，每次遍历记录数组最小值，并且用计算当前值和最小值之差为利润，记录最大的利润”“”class Solution(object): def maxProfit(self, prices): """ :type prices: List[int] :rtype: int """
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摘要：# Definition for a binary tree node. # class TreeNode(object): # def __init__(self, x): # self.val = x # self.left = None # self.right = None # 递归，中序遍
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摘要：#用二分查找法class Solution(object): def searchRange(self, nums, target): """ :type nums: List[int] :type target: int :rtype: List[int] """ first = 0 last =
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摘要：# 递归方法解决class Solution(object): def letterCombinations(self, digits): """ :type digits: str :rtype: List[str] """ d = {"2":"abc", "3":"def", "4":"ghi"
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摘要：class Solution(object): def isValid(self, s): """ :type s: str :rtype: bool """ stack = [] #存放符号 d = {"]": "[", ")":"(", "}":"{"} “”“ 判断符号是否是结束符号，如果是，
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