Problem Link: http://oj.leetcode.com/problems/longest-consecutive-sequence/ This problem is a classical problem where we can reduce the running time by the help of hash table. By given a list of numbers, we can find the longest consecutive sequence b…

Longest Consecutive Sequence 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.…

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…

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…

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 run in…

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 run in…

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…

描述 输入一个乱序的连续数列,输出其中最长连续数列长度,要求算法复杂度为 O(n) . 输入 54,55,300,12,56 输出 3 通常我们看有没有连续序列时 找某个数有没有的前后的数,比如看到55,我们会下意识找56,57...54,53...这道题做法也是这样. 我的做法是用map映射,键为列表中的每个数,值为1.然后遍历数组,比如数为55,找这个数的前后有没有map映射后值为1的,有的话sum++,为了防止重复遍历需要把遍历过的数的映射值改成-1. class Solution { p…

题目链接:https://leetcode.com/problems/longest-palindromic-substring/ 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. 解题思路:p…