随笔分类 - leetcode刷题总结
https://oj.leetcode.com/
摘要：Given a linked list, swap every two adjacent nodes and return its head.For example,Given1->2->3->4, you should return the list as2->1->4->3.Your algor...
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摘要：Given two words (startandend), and a dictionary, find the length of shortest transformation sequence fromstarttoend, such that:Only one letter can be ...
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摘要：A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy ...
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摘要：Given a stringS, find the longest palindromic substring inS. You may assume that the maximum length ofSis 1000, and there exists one unique longest pa...
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摘要：Say you have an array for which theithelement is the price of a given stock on dayi.If you were only permitted to complete at most one transaction (ie...
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摘要：Given a linked list and a valuex, partition it such that all nodes less thanxcome before nodes greater than or equal tox.You should preserve the origi...
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摘要：Given a sorted linked list, delete all duplicates such that each element appear onlyonce.For example,Given1->1->2, return1->2.Given1->1->2->3->3, retu...
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摘要：Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }Populate each next pointe...
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摘要：Given a matrix ofmxnelements (mrows,ncolumns), return all elements of the matrix in spiral order.For example,Given the following matrix:[ [ 1, 2, 3 ],...
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摘要：Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".题解：用栈就行了代码： 1 class Solution {...
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摘要：Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement is not possibl...
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摘要：The set[1,2,3,…,n]contains a total ofn! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie...
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摘要：Given a binary tree, return theinordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[1,3,2].Note:Recursive solution is trivial, could you do it iteratively?解题：果然不能晚上做题，效率好低。看了讨论才学会的解法。设置一个指针next指向当前访问的节点，如果它不为空，就把它压栈，并且下一个访问它的左节点；如果它为空，就从栈顶一定是它的父...
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摘要：Given a binary tree, return thepreordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[1,2,3].Not...
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摘要：Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?解题：开始进入一个误区，跟循环链表搞混了，其实这个环的开头可以不在head这里，例如...
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摘要：Givenn, how many structurally uniqueBST's(binary search trees) that store values 1...n?For example,Givenn= 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 ...
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摘要：Say you have an array for which theithelement is the price of a given stock on dayi.Design an algorithm to find the maximum profit. You may complete a...
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摘要：Reverse digits of an integer.Example1:x = 123, return 321Example2:x = -123, return -321解题：设定一个变量sum存放反转后的答案，每次取输入x的最后一位n，并用sum = sum*10+n更新sum。例如题设的数字123，初始sum为0，过程如下：取末尾的3，sum=3，x=12取末尾的2，sum=32，x=1取末尾的1，sum=321，x=0特别注意x一开始就是0的处理，直接返回0就可以了。代码： 1 class Solution { 2 public: 3 int reverse(int x) {...
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摘要：Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical an...
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摘要：Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest le...
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