题目 Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example, Given [100, 4, 200, 1, 3, 2], The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4. Your algorithm should ru…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not v…

原题链接在这里:https://leetcode.com/problems/binary-tree-longest-consecutive-sequence-ii/description/ 题目: Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasi…

原题链接在这里:https://leetcode.com/problems/binary-tree-longest-consecutive-sequence/ 题目: Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tre…

Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not v…

题目 Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the longest valid parentheses substring is "()", which has length = 2. Another example i…

题目 Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. 分析 求给定字符串的最长回文子串. 这道题有下面三种解决思路: 暴力法,二层遍历,判断[i,j]子串是否回文,且同时记录最长长度: 显然的,暴力…

题目: Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. For "bbbbb" the longest s…

题目 Write a function to find the longest common prefix string amongst an array of strings. 分析 该题目是求一个字符串容器中所有字符串的最长公共前缀. AC代码 class Solution { public: string longestCommonPrefix(vector<string>& strs) { if (strs.size() == 0) return ""; e…