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摘要： Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn't 阅读全文

摘要： Given a string s , find the length of the longest substring t that contains at most 2 distinct characters. Example 1: Example 2: 阅读全文

摘要： https://www.geeksforgeeks.org/shortest-path-between-two-nodes-in-array-like-representation-of-binary-tree/ 阅读全文

摘要： time complexity is O(n) Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA 阅读全文

摘要： ( bfs is easy, instead use preorder dfs right first and then left) Given a binary tree, imagine yourself standing on the right side of it, return the 阅读全文

摘要： https://github.com/tongzhang1994/Facebook-Interview-Coding/blob/master/257.%20Binary%20Tree%20Paths.java Given a binary tree, return all root-to-leaf 阅读全文

摘要： Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and 阅读全文

摘要： not tested yet 阅读全文

摘要： example: 1 1 1 2 for the first pos, we can chose 1 and 2 , skip the two 1s in the middle , the way we skip these 1s is within the for loop, we only ad 阅读全文

摘要： 653 two sum iv - input is a bst Approach #1 Using HashSet[Accepted] The simplest solution will be to traverse over the whole tree and consider every p 阅读全文

摘要： Given the head of a graph, return a deep copy (clone) of the graph. Each node in the graph contains a label (int) and a list (List[UndirectedGraphNode 阅读全文

摘要： Given a matrix that is filled with ‘O’, ‘G’, and ‘W’ where ‘O’ represents open space, ‘G’ represents guards and ‘W’ represents walls in a Bank. Replac 阅读全文

摘要： 大班文档有java solution 强化 5 x.y z is similar 阅读全文

摘要： 120. Triangle Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. For example, given the following triangle [ [2], ... 阅读全文

摘要： 377. Combination Sum IV Given an integer array with all positive numbers and no duplicates, find the number of possible combinations that add up to a positive integer target. Example: nums = [1, 2, ... 阅读全文

摘要： Given a 2D binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area. Example: Input: 1 0 1 0 0 1 0 1 1 1 阅读全文

摘要： example： input is two non-overlapping list of intervals , output is the list of overlaps l1 : [0, 2], [5, 7]. [9, 11] l2: [1, 3], [6, 10] overlap is [ 阅读全文

摘要： 实现 next（）， hasNext() . Follow up： 实现 remove, remove 要求删除next（）last visited node and its subtree. 阅读全文

摘要： k sorted list iterator. 写个被多次 call 的 getNext()。没要求用 iterator, 于是 heap 秒了。面试官表示很满意。 阅读全文

摘要： merge sorted iterator 这个小班 讲过， 小班文档上应该有 阅读全文