随笔分类 - leetcode刷题总结
https://oj.leetcode.com/
摘要：Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:A solution using O(n) space is ...
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摘要：Given a binary tree, return thebottom-up level ordertraversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For exa...
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摘要：Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2).You are given a target value t...
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摘要：There are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car with an unlimited gas tank and it costs...
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摘要：There areNchildren standing in a line. Each child is assigned a rating value.You are giving candies to these children subjected to the following requi...
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摘要：Given a stringsand a dictionary of wordsdict, add spaces insto construct a sentence where each word is a valid dictionary word.Return all such possibl...
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摘要：Given a stringsand a dictionary of wordsdict, determine ifscan be segmented into a space-separated sequence of one or more dictionary words.For exampl...
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摘要：Given a singly linked listL:L0→L1→…→Ln-1→Ln,reorder it to:L0→Ln→L1→Ln-1→L2→Ln-2→…You must do this in-place without altering the nodes' values.For exam...
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摘要：Sort a linked list using insertion sort.题解：实现链表的插入排序。要注意的地方就是，处理链表插入的时候尽量往当前游标的后面插入，而不要往前面插入，后者非常麻烦。所以每次利用kepeler.next.val和head.val比较大小，而不是kepeler.val...
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摘要：Sort a linked list inO(nlogn) time using constant space complexity.题解：实现一个链表的归并排序即可。主要分为三部分：1.找到中点并返回的函数findMiddle;2.归并函数merge;3.排序函数sortList。数组的findM...
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摘要：Determine whether an integer is a palindrome. Do this without extra space.Some hints:Could negative integers be palindromes? (ie, -1)If you are thinki...
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摘要：Given a binary tree, find the maximum path sum.The path may start and end at any node in the tree.For example:Given the below binary tree, 1 ...
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摘要：Givennpoints on a 2D plane, find the maximum number of points that lie on the same straight line.题解：思路比较简单，每条直线都可以表示为y=kx+b，所以对于任意三点，如果它们共线，那么它们中任意两点的...
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摘要：Evaluate the value of an arithmetic expression inReverse Polish Notation.Valid operators are+,-,*,/. Each operand may be an integer or another express...
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摘要：Given a digit string, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephon...
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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?题解：参见http://www.cnblogs.com/sunshineatnoon...
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摘要：Given a stringsconsists of upper/lower-case alphabets and empty space characters' ', return the length of last word in the string.If the last word doe...
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摘要：Given a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,...
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摘要：Given an integern, generate a square matrix filled with elements from 1 ton2in spiral order.For example,Givenn=3,You should return the following matri...
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摘要：Given amxnmatrix, if an element is 0, set its entire row and column to 0. Do it in place.题解：因为题目要求原地算法，所以我们只能利用矩阵第一行和第一列存放置零信息。首先遍历第一行和第一列，看他们是否需要全部置零...
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