poiop221-优快云博客

原创数组：Remove Element&Merge Sorted Array&First Missing Positive

Remove Elementpublic int removeElement(int[] nums, int val) { int count = 0; for(int i=0;i<nums.length;i++){ if(nums[i]!=val){ nums[count] = nums[i];

2015-10-22 11:42:29 418

原创遍历技巧:2,3,4sum&3sum closest&set matrix zeroes&Container With Most Water

2 sumpublic class Solution { public int[] twoSum(int[] nums, int target) { int[] res = new int[2]; HashMap map = new HashMap(); for(int i=0;i<nums.length;i++){

2015-10-21 09:31:36 426

转载 Median of Two Sorted Arrays

There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).public class Solution {

2015-10-05 08:27:17 393

转载 Candy

There are N children standing in a line. Each child is assigned a rating value.You are giving candies to these children subjected to the following requirements:Each child must have at least on

2015-10-02 06:38:41 386

转载 Regular Expression Matching

Implement regular expression matching with support for '.' and '*'.'.' Matches any single character.'*' Matches zero or more of the preceding element.The matching should cover the entire input st

2015-10-02 06:34:14 271

转载 Best Time to Buy and Sell Stock IV

Say you have an array for which the ith element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete at most k transactions.public class Solu

2015-10-02 06:21:58 340

转载 Minimum Window Substring

Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n).For example,S = "ADOBECODEBANC"T = "ABC"Minimum window is "BAN

2015-10-02 06:14:05 239

转载 Dungeon Game

https://leetcode.com/problems/dungeon-game/public class Solution { public int calculateMinimumHP(int[][] dungeon) { if (dungeon == null || dungeon.length == 0 || dungeon[0].length == 0) r

2015-10-02 06:03:04 283

转载 Expression Add Operators

Given a string that contains only digits 0-9 and a target value, return all possibilities to add binaryoperators (not unary) +, -, or * between the digits so they evaluate to the target value.

2015-10-02 05:57:47 291

转载 Shortest Palindrome

Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation.For exam

2015-10-02 05:48:01 249

转载 Wildcard matching

Implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (including the empty sequence).The matching should cover t

2015-10-02 04:30:18 247

转载 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

2015-09-30 23:49:28 310

原创 LRU cache

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

2015-09-30 23:26:39 265

转载 Text Justification

Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.You should pack your words in a greedy approach; that i

2015-09-28 03:23:59 234

转载 Word Ladder II(BFS + DFS)

Given two words (beginWord and endWord), and a dictionary's word list, find all shortest transformation sequence(s) from beginWord to endWord, such that:Only one letter can be changed at a timeEac

2015-09-28 02:55:17 315

转载 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./* * A line is determined by two factors,say y=ax+b * * If two points(x1,y1) (x2,

2015-09-27 23:44:03 324

原创 Valid Number

public class Solution { public boolean isNumber(String s) { s = s.trim(); boolean pointSeen = false; boolean eSeen = false; boolean numberSeen = false; boolean numberAfterE =

2015-09-27 21:25:30 323

转载 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

2015-09-27 11:38:48 240

转载 Fraction to Recurring Decimal

Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.If the fractional part is repeating, enclose the repeating part in parentheses.

2015-09-27 11:14:09 267

转载 Surrounded Regions

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 X

2015-09-27 10:44:49 266

转载 Divide Two Integers

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

2015-09-27 03:45:02 213

转载 Integer to English Words

Convert a non-negative integer to its english words representation. Given input is guaranteed to be less than 231 - 1.For example,123 -> "One Hundred Twenty Three"12345 -> "Twelve Thousand Th

2015-09-27 03:23:39 239

转载 Reverse Words in a String

Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".public class Solution { public String reverseWords(String s) {

2015-09-27 02:38:32 202

转载 Contains Duplicate III

Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i an

2015-09-27 02:26:17 237

原创 Decode ways

A message containing letters from A-Z is being encoded to numbers using the following mapping:'A' -> 1'B' -> 2...'Z' -> 26Given an encoded message containing digits, determine the total nu

2015-09-26 23:04:16 230

转载 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

2015-09-26 04:40:30 217

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

2015-09-26 02:58:15 206

转载 Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product.For example, given the array [2,3,-2,4],the contiguous subarray [2,3] has the largest

2015-09-24 11:00:25 221

转载 Simplify Path

Given an absolute path for a file (Unix-style), simplify it.For example,path = "/home/", => "/home"path = "/a/./b/../../c/", => "/c"click to show corner cases.Corner Cases:Did

2015-09-24 10:05:04 269

原创 Validate Binary Search Tree

Given a binary tree, determine if it is a valid binary search tree (BST).Assume a BST is defined as follows:The left subtree of a node contains only nodes with keys less than the node's key.Th

2015-09-24 09:35:07 205

转载 Maximal Square

Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 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 0

2015-09-23 05:04:44 189

转载 Number of Digit One(数学找规律)

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

2015-09-23 03:29:31 249

转载 Ugly Number II

Write a program to find the n-th ugly number.Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 1, 2, 3, 4, 5, 6, 8, 9, 10, 12 is the sequence of the first

2015-09-23 03:12:17 189

转载 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

2015-09-23 02:19:15 208

原创 Word Search

Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically

2015-09-23 01:34:01 206

转载 Multiply Strings

Given two numbers represented as strings, return multiplication of the numbers as a string.public class Solution { public String multiply(String num1, String num2) { if (num1 == null ||

2015-09-22 10:43:40 196

转载 Count Complete Tree Nodes

Given a complete binary tree, count the number of nodes.Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely fille

2015-09-22 10:20:25 191

转载 Restore IP Addresses(DFS的巅峰)

Given a string containing only digits, restore it by returning all possible valid IP address combinations.For example:Given "25525511135",return ["255.255.11.135", "255.255.111.35"]. (Order

2015-09-22 10:07:04 214

转载 Evaluate Reverse Polish Notation

Evaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators are +, -, *, /. Each operand may be an integer or another expression.Some examples: ["2", "1",

2015-09-22 02:54:53 209

转载 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

2015-09-21 22:20:42 326

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