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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 ... 阅读全文

摘要： Given two wordsword1andword2, find the minimum number of steps required to convertword1toword2. (each operation is counted as 1 step.)You have the fol... 阅读全文

摘要： Given an array withnobjects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, wh... 阅读全文

摘要： Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where "adjace... 阅读全文

摘要： Write a program to find the node at which the intersection of two singly linked lists begins.For example, the following two linked lists:A: a... 阅读全文

摘要： Givennpairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, givenn= 3, a solution set is:"((()))... 阅读全文

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... 阅读全文

摘要： Given an indexk, return thekthrow of the Pascal's triangle.For example, givenk= 3,Return[1,3,3,1].Note:Could you optimize your algorithm to use onlyO(... 阅读全文

摘要： Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.分析：该题是经典的串匹配，我们可以用KMP来解，时间... 阅读全文

摘要： Given a binary tree, return thepostordertraversal of its nodes' values.For example:Given binary tree{1,#,2,3}, 1 \ 2 / 3return[3,2,1].No... 阅读全文