摘要：要知道单源最短路径的的两种算法--bellman-ford算法以及dijkstra算法之前，首先我们要来了解一种技术：松弛技术。所谓的松弛技术，实际上用一串代码即可解释：　RELAX（u，v，w） if d(v）> d(u) + w(v,u) then d(v) <---- d(u)+w(v,u) pai(v)<----u这就是所谓的松弛一条边（u,v)的过程。意思就是：我们想要找到v的最短路径，那么我们这时候已经知道了到u的最短路径，那么利用u的最短路径+（u,v)的长度， 看这个长度是否比当前v上标明的，到v的最短路径还要短。如果是的话，就把最短的值给d(v),v的父.. 阅读全文

摘要：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 O(n) complexity.这道题貌似在陈利人的微博上看到过，当时是有思路的：即采用hash的方法。但是再 阅读全文

摘要：Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.An example is the root-to-leaf path 1->2->3 which represents the number 123.Find the total sum of all root-to-leaf numbers.For example, 1 / \ 2 3The root-to-leaf path 1->2 represents the num 阅读全文

摘要：Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'.A region is captured by flipping all 'O's into 'X's in that surrounded region .For example,X X X XX O O XX X O XX O X XAfter running your function, the board should be:X X X XX X X 阅读全文

摘要：Given a string s, partition s such that every substring of the partition is a palindrome.Return all possible palindrome partitioning of s.For example, given s = "aab", Return [ ["aa","b"], ["a","a","b"] ]不太清楚。网上说是用dfs来做，但是可能因为自己水平不够，不明白如何算是 阅读全文