zhixin_wen95-优快云博客

原创 Longest Valid Parentheses

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 "()",

2015-11-19 15:58:39 287

原创 Word Pattern II

Given a pattern and a string str, find if str follows the same pattern.Here follow means a full match, such that there is a bijection between a letter in pattern and a non-emptysubstring in str.

2015-11-19 13:54:33 716

原创 Word Pattern

Given a pattern and a string str, find if str follows the same pattern.Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.

2015-11-19 13:21:22 345

原创 Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.用了一个dumb head,。对于这种header不确定的list，可以用dumb header，代码会整洁不

2015-11-19 12:50:37 296

原创 Merge Sorted Array

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.Note:You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold add

2015-11-19 12:26:15 337

原创 Lowest Common Ancestor of a Binary Search Tree

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined betw

2015-11-19 12:10:18 235

转载 Shortest Word Dsitance III

word1 and word2 can be equal//C++: 20msclass Solution {public: int shortestWordDistance(vector& words, string word1, string word2) { int n = words.size(); int p1 = -1, p2 =

2015-11-13 05:44:35 248

转载 Shortest Word Distance II

This is a follow up of Shortest Word Distance. The only difference is now you are given the list of words and your method will be called repeatedly many times with different parameters. How would you

2015-11-13 05:43:00 273

原创 Shortest Word Distance

Given a list of words and two words word1 and word2, return the shortest distance between these two words in the list.For example,Assume that words = ["practice", "makes", "perfect", "coding", "

2015-11-13 04:53:55 321

原创 Two Sum

Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to the target, whe

2015-11-13 04:03:53 228

原创 Find Minimum in Rotated Sorted Array II

Follow up for "Find Minimum in Rotated Sorted Array":What if duplicates are allowed?Would this affect the run-time complexity? How and why?Suppose a sorted array is rotated at some pivot unk

2015-11-13 03:53:28 270

原创 Find Minimum in Rotated Sorted Array

Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).Find the minimum element.You may assume no duplicate exists in

2015-11-13 03:29:51 226

原创 Maximum Product Subarray

public class Solution { public int maxProduct(int[] nums) { int maxValue = nums[0]; int minValue = nums[0]; int max = nums[0]; for(int i = 1; i < nums.length; i++){

2015-11-12 16:33:57 228

原创 [LeetCode] Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.For example, given the array [−2,1,−3,4,−1,2,1,−5,4],the contiguous subarray [4,−1,2,1] ha

2015-11-12 16:13:12 187

原创 Graph Valid Tree

Problem Description:Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree.Fo

2015-11-12 14:44:24 313

原创 Isomorphic Strings

Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be replaced with anot

2015-11-12 13:31:47 248

原创 Repeated DNA Sequences

All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: "ACGAATTCCG". When studying DNA, it is sometimes useful to identify repeated sequences within the DNA.Wri

2015-11-12 10:48:00 311

Given a binary tree where all the right nodes are either leaf nodes with a sibling (a left node that shares the same parent node) or empty, flip it upside down and turn it into a tree where the origin

2015-11-12 07:37:28 270

原创 Longest Increasing Subsequence

Given an unsorted array of integers, find the length of longest increasing subsequence.For example,Given [10, 9, 2, 5, 3, 7, 101, 18],The longest increasing subsequence is [2, 3, 7, 101], ther

2015-11-12 06:29:15 269

原创 Kth Largest Element in an Array

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.For example,Given [3,2,1,5,6,4] and k = 2, return 5.

2015-11-11 14:41:29 224

原创 Serialize and Deserialize Binary Tree

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be

2015-11-11 13:38:57 290

原创 Construct Binary Tree from Preorder and Inorder Traversal

Given preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in the tree.Subscribe to see which companies asked this questio

2015-11-11 12:03:36 213

原创 Search for a Range

Given a sorted array of integers, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the order of O(log n).If the target is not found

2015-11-10 12:00:32 225

原创【LeetCode】Binary Tree Zigzag Level Order Traversal

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 alternate between).For example:Given binary

2015-11-08 04:26:20 202

原创 Flowing Water

输入是一个 N*N的矩阵，代表地势高度。如果下雨水流只能流去比他矮或者一样高的地势。矩阵左边和上边是太平洋，右边和下边是大西洋。求出所有的能同时流到两个大洋的点。For example:12345678910Pacific: ~Atlantic: *~ ~ ~ ~ ~ ~ ~~ 1 2 2 3 (5) *~ 3

2015-11-07 14:29:05 347

原创 [LeetCode] Merge Intervals

Given a collection of intervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18]./** * Definition for an interval. * public

2015-11-07 13:20:00 213

原创【Leetcode】Divide Two Integers

Divide two integers without using multiplication, division and mod operator.If it is overflow, return MAX_INT.简单解法：O(dividend/divisor)public class Solution { public int divide(int divide

2015-11-03 15:50:34 195

原创 [LeetCode] Add Two Numbers

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a link

2015-10-29 13:29:31 217

原创 Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. Y

2015-10-29 13:10:05 200

原创 [LeetCode] Number of Digit One

Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.For example:Given n = 13,Return 6, because digit 1 occurred in the follow

2015-10-29 11:48:44 213

原创 [LeetCode] Insert Interval

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).You may assume that the intervals were initially sorted according to their start times.E

2015-10-28 12:25:48 154

原创 [Leetcode] Compare Version Numbers

Compare two version numbers version1 and version2.If version1 > version2 return 1, if version1 version2 return -1, otherwise return 0.You may assume that the version strings are non-empty and co

2015-10-28 05:33:57 266

原创 [Leetcode]Kth Smallest Element in a BST

Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.Note: You may assume k is always valid, 1 ≤ k ≤ BST's total elements.Follow up:What if the

2015-10-28 05:32:21 201

原创 Basic Calculator II

Implement a basic calculator to evaluate a simple expression string.The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer division should

2015-10-25 13:22:24 217

原创 [LeetCode] Palindrome Linked List

Given a singly linked list, determine if it is a palindrome.Follow up:Could you do it in O(n) time and O(1) space?先翻转后半段，再比较/** * Definition for singly-linked list. * public class ListNo

2015-10-25 09:12:47 206

原创 [LeetCode] Basic Calculator

Implement a basic calculator to evaluate a simple expression string.The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers and em

2015-10-25 07:01:28 209

原创 [LeetCode] Valid Anagram

Given two strings s and t, write a function to determine if t is an anagram of s.For example,s = "anagram", t = "nagaram", return true.s = "rat", t = "car", return false.public class S

2015-10-25 03:11:59 204

原创 [LeetCode] Copy List with Random Pointer

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy of the list.最简单的方法是参照clone graph，利用一个HashM

2015-10-25 02:15:08 204

原创 [LeetCode] Multiply Strings

Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-negative.public class Solution { pub

2015-10-24 11:40:28 228

原创 [Leetcode] 3Sum

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a triplet (a,b,c)

2015-10-18 11:34:27 137

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