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转载 Morris 二叉搜索树遍历模板

Morris Traversal是o(n)时间复杂度，o(1)空间复杂度的BST遍历方法。下面是Morris Traversal模板：public void morrisInorderTraverse() { Node cur = root; while (cur != null) { if (cur.left == null) { ...

2019-09-08 09:58:42 238

镜像类docker build --rm=true . 构建镜像docker pull ${IMAGE} 安装镜像docker images 显示已经安装的镜像docker images --no-trunc 显示已经安装镜像的详细内容docker rmi ${IMAGE_ID} 删除指定镜像docker rmi $(docker images | grep “^” | awk “{print $...

2018-03-29 07:53:22 323 1

原创 ROS配置python开发环境（pycharm）问题汇总

1. pycharm 无法使用ros的module问题，如rospy。在开启pycharm的时候使用命令 "sudo bash -i /home/shouyi/pycharm/bin/pycharm.sh"。这里加 -i 是为了可以使用ros环境的module。（待续……）...

2018-03-29 07:50:03 2269 6

原创 617. Merge Two Binary Trees

Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not. You need to merge them into a new binary tre

2017-08-18 06:09:07 279

原创 335. Self Crossing

You are given an array x of n positive numbers. You start at point (0,0) and moves x[0] metres to the north, then x[1] metres to the west, x[2] metres to the south, x[3] metres to the east and s

2017-08-18 03:00:52 448

原创 384. Shuffle an Array

Shuffle a set of numbers without duplicates.Example:// Init an array with set 1, 2, and 3.int[] nums = {1,2,3};Solution solution = new Solution(nums);// Shuffle the array [1,2,3] and return

2017-08-16 04:59:40 222

原创 149. Max Points on a Line

Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.这道题应该注意只要是在一条直线上就算。第一反应是用HashMap来存斜率，但是如果double精确到小数点后好多位之后就趋于相等，key值就相等了，所以一般不要用double作key。这里可以用

2017-08-12 04:46:12 286

原创 540. Single Element in a Sorted Array

Given a sorted array consisting of only integers where every element appears twice except for one element which appears once. Find this single element that appears only once. Example 1:Input:

2017-08-09 13:06:54 260

原创二叉树遍历模板（前序，中序，后序）

Pre Order Traversepublic List preorderTraversal(TreeNode root) { List result = new ArrayList<>(); Deque stack = new ArrayDeque<>(); TreeNode p = root; while(!stack.isEmpty() || p !

2017-07-26 05:04:30 626

原创 A clean DP solution which generalizes to k transactions

有一个解决股票买卖问题（Best Time to Buy and Sell Stock）的模板，可以推广到买卖n次。class Solution {public: int maxProfit(vector &prices) { // f[k, ii] represents the max profit up until prices[ii] (Note: NOT en

2017-07-24 13:02:36 285

原创 Longest Palindromic Substring

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.Have you met t

2017-07-02 01:40:57 306

原创 Subarray Sum Closest

Given an integer array, find a subarray with sum closest to zero. Return the indexes of the first number and last number.Have you met this question in a real interview? YesExample

2017-07-01 02:27:31 358

原创 518. Coin Change 2

You are given coins of different denominations and a total amount of money. Write a function to compute the number of combinations that make up that amount. You may assume that you have infinite numbe

2017-06-25 07:28:06 1744

原创 85. Maximal Rectangle

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area.For example, given the following matrix:1 0 1 0 01 0 1 1 11 1 1 1 11 0 0 1

2017-06-24 13:20:37 234

原创 480. Sliding Window Median

Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value.Examples: [2,3,4] , the median

2017-06-23 16:23:16 304

原创 239. Sliding Window Maximum

Given an array nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k numbers in the window. Each time the sliding window

2017-06-23 14:05:15 288

原创 84. Largest Rectangle in Histogram

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.Above is a histogram where width o

2017-06-23 13:19:31 281

原创 212. Word Search II

Given a 2D board and a list of words from the dictionary, find all words in the board.Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those hor

2017-06-23 01:58:09 296

原创 295. Find Median from Data Stream

Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value.Examples: [2,3,4] , the median

2017-06-22 01:24:03 223

原创 407. Trapping Rain Water II

Given an m x n matrix of positive integers representing the height of each unit cell in a 2D elevation map, compute the volume of water it is able to trap after raining.Note:Both m and n are l

2017-06-21 08:28:51 245

原创 42. Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. For example, Given [0,1,0,2,1,0,1,3,2,1,2,1

2017-06-20 06:21:39 255

原创 388. Longest Absolute File Path

Suppose we abstract our file system by a string in the following manner:The string "dir\n\tsubdir1\n\tsubdir2\n\t\tfile.ext" represents:dir subdir1 subdir2 file.extThe direc

2017-06-19 14:10:37 235

原创 146. LRU Cache

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and put.get(key) - Get the value (will always be positive) of the key i

2017-06-19 12:38:16 387

原创 560. Subarray Sum Equals K

Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k.Example 1:Input:nums = [1,1,1], k = 2Output: 2Note:

2017-06-17 13:34:13 379

原创 398. Random Pick Index

Given an array of integers with possible duplicates, randomly output the index of a given target number. You can assume that the given target number must exist in the array.Note:The array size c

2017-06-17 13:16:05 242

原创 382. Linked List Random Node

Given a singly linked list, return a random node's value from the linked list. Each node must have the same probability of being chosen.Follow up:What if the linked list is extremely large and i

2017-06-17 13:01:00 226

原创 307. Range Sum Query - Mutable

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.The update(i, val) function modifies nums by updating the element at index i to val.Examp

2017-06-17 09:00:34 282

原创 604. Design Compressed String Iterator

Design and implement a data structure for a compressed string iterator. It should support the following operations: next and hasNext.The given compressed string will be in the form of each letter

2017-06-17 02:05:11 494

原创 353. Design Snake Game

Design a Snake game that is played on a device with screen size = width x height. Play the game online if you are not familiar with the game.The snake is initially positioned at the top left cor

2017-06-16 16:41:06 606

原创 379. Design Phone Directory

Design a Phone Directory which supports the following operations:get: Provide a number which is not assigned to anyone.check: Check if a number is available or not.release: Recycle or release

2017-06-16 14:54:07 360

原创 348. Design Tic-Tac-Toe

Design a Tic-tac-toe game that is played between two players on a n x n grid.You may assume the following rules:A move is guaranteed to be valid and is placed on an empty block.Once a winning

2017-06-16 11:43:13 324

原创 362. Design Hit Counter

Design a hit counter which counts the number of hits received in the past 5 minutes.Each function accepts a timestamp parameter (in seconds granularity) and you may assume that calls are being mad

2017-06-16 09:16:45 334

原创 251. Flatten 2D Vector

Implement an iterator to flatten a 2d vector.For example,Given 2d vector = [ [1,2], [3], [4,5,6]]By calling next repeatedly until hasNext returns false, the order of elements r

2017-06-16 03:18:53 294

原创 284. Peeking Iterator

Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek()operation -- it essentially peek() at the element that will be r

2017-06-16 01:48:05 309

原创 281. Zigzag Iterator

Given two 1d vectors, implement an iterator to return their elements alternately.For example, given two 1d vectors:v1 = [1, 2]v2 = [3, 4, 5, 6]By calling next repeatedly until hasNext

2017-06-15 15:29:30 281

原创 444. Sequence Reconstruction

Check whether the original sequence org can be uniquely reconstructed from the sequences in seqs. The org sequence is a permutation of the integers from 1 to n, with 1 ≤ n ≤ 104. Reconstruction me

2017-06-15 12:16:15 970

原创 399. Evaluate Division

Equations are given in the format A / B = k, where A and B are variables represented as strings, and k is a real number (floating point number). Given some queries, return the answers. If the ans

2017-06-15 06:43:26 308

原创 310. Minimum Height Trees

For a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum height are called mini

2017-06-15 03:15:04 245

原创 286. Walls and Gates

You are given a m x n 2D grid initialized with these three possible values.-1 - A wall or an obstacle.0 - A gate.INF - Infinity means an empty room. We use the value 231 - 1 = 2147483647 to repr

2017-06-15 01:53:46 320

原创 130. Surrounded Regions

Given a 2D board containing 'X' and 'O' (the letter 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,

2017-06-14 12:30:41 238

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