03 2017 档案
摘要：动态规划算法的基本要素： 1 最优子结构性质当问题的最优解包含了其子问题的最优解时，称该问题具有最优子结构性质。2 重叠子问题性质 动态规划算法对每个问题只解一次，将其解保存在一个表格中，当再次需要解此问题时，用常数时间查看一下结果。因此，用动态规划算法通常只需要多项式时间。 备忘录方法：•用一个表
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摘要：Given a binary search tree and a node in it, find the in-order successor of that node in the BST. Note: If the given node has no in-order successor in
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摘要：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, ex
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摘要：Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target. Note: Given target value is a floati
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摘要：Given a non-empty binary search tree and a target value, find k values in the BST that are closest to the target. Note: Given target value is a floati
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摘要：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
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摘要：Implement an iterator over a binary search tree (BST). Your iterator will be initialized with the root node of a BST. Calling next() will return the n
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摘要：Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, return [3,2,1]. Note: Recursive sol
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摘要：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
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摘要：Given an array of numbers, verify whether it is the correct preorder traversal sequence of a binary search tree. You may assume each number in the seq
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摘要：Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, return [1,2,3]. Note: Recursive solu
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摘要：Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree [1,null,2,3], return [1,3,2]. Note: Recursive so
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摘要：Given two sparse matrices A and B, return the result of AB. You may assume that A's column number is equal to B's row number. Example:
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摘要：Given two strings s and t which consist of only lowercase letters. String t is generated by random shuffling string s and then add one more letter at
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摘要：我觉得这是一个非常有意思的问题，Math.abs(-2147483648)的返回值应该是什么？ java计算结果 为什么没有得到正数结果呢？ 首先我们先看下java区分整数正负的原理。在二进制的情况下，java使用0和1来代表正和负，最高位——左面第一位为1代表负数，最高位为0就代表正数。在32位的
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摘要：Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating
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摘要：You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time
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摘要：You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/ve
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摘要：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 lette
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摘要：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 lette
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摘要：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 occurrenc
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摘要：Given a string s, find the longest palindromic subsequence's length in s. You may assume that the maximum length of s is 1000. Example 1:Input: Output
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摘要：递归的基本概念:程序调用自身的编程技巧称为递归,是函数自己调用自己. 一个函数在其定义中直接或间接调用自身的一种方法,它通常把一个大型的复杂的问题转化为一个与原问题相似的规模较小的问题来解决,可以极大的减少代码量.递归的能力在于用有限的语句来定义对象的无限集合. 使用递归要注意的有两点: 1)递归就
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摘要：Given a list of unique words, find all pairs of distinct indices (i, j) in the given list, so that the concatenation of the two words, i.e. words[i] +
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摘要：快速选择算法,是一种能在大致O(N)的时间内选取数组中第k大或者k小的算法.其基本思路与快速排序算法类似,也是分治的思想. 其实这个算法是个基础算法,但是不常用,所以今天编的时候错了POJ2388,才有了这篇文章. 下面几段代码,尤其要注意的是 while(i<j) 还是 while(i<=j) 程
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摘要：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 exam
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摘要：Given a non-empty array of integers, return the k most frequent elements. For example,Given [1,1,1,2,2,3] and k = 2, return [1,2]. Note: You may assum
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摘要：Given two arrays, write a function to compute their intersection. Example:Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2]. Note: Each elemen
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摘要：Given two arrays, write a function to compute their intersection. Example:Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2]. Note: Each element i
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摘要：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
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摘要：Write a program to solve a Sudoku puzzle by filling the empty cells. Empty cells are indicated by the character '.'. You may assume that there will be
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摘要：Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules. The Sudoku board could be partially filled, where empty cells are filled wit
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摘要：Given a string s and a non-empty string p, find all the start indices of p's anagrams in s. Strings consists of lowercase English letters only and the
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摘要：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 =
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摘要：Given an array of strings, group anagrams together. For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], Return: Note: All inputs will be i
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摘要：Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors. OJ's undirected graph serialization: Nodes are labeled
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摘要：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
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摘要：Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between iand j equals
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摘要：Given n points on a 2D plane, find if there is such a line parallel to y-axis that reflect the given points. Example 1: Given points = [[1,1],[-1,1]],
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摘要：Given n points on a 2D plane, find the maximum number of points that lie on the same straight line. 本题是比较难的题目，首先需要弄懂一点，就是最大公约数是最大的可整除数，也就是默认为k值（y=kx+b
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摘要：Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. For example, given n = 12,
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摘要：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,
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摘要：Description: Count the number of prime numbers less than a non-negative number, n. 本题不知道为什么，不可以使用hashtable来做，如果用了就超时了，只能用数组来存储，代码如下：
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摘要：Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For exa
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摘要：Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive intege
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摘要：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 sh
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摘要：Given an array of integers and an integer k, you need to find the number of unique k-diff pairs in the array. Here a k-diff pair is defined as an inte
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摘要：Given a picture consisting of black and white pixels, and a positive integer N, find the number of black pixels located at some specific row Rand colu
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摘要：Given a picture consisting of black and white pixels, find the number of black lonely pixels. The picture is represented by a 2D char array consisting
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摘要：In LLP world, there is a hero called Teemo and his attacking can make his enemy Ashe be in poisoned condition. Now, given the Teemo's attacking ascend
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摘要：Assume you have an array of length n initialized with all 0's and are given k update operations. Each operation is represented as a triplet: [startInd
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摘要：Given a binary array, find the maximum number of consecutive 1s in this array if you can flip at most one 0. Example 1: Note: The input array will onl
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摘要：Given a binary array, find the maximum number of consecutive 1s in this array. Example 1: Note: The input array will only contain 0 and 1. The length
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摘要：Given a non-empty array of integers, return the third maximum number in this array. If it does not exist, return the maximum number. The time complexi
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摘要：Given a collection of integers that might contain duplicates, nums, return all possible subsets. Note: The solution set must not contain duplicate sub
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摘要：Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. Example:
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摘要：Design a data structure that supports all following operations in average O(1) time. Example:
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摘要：Given a string that consists of only uppercase English letters, you can replace any letter in the string with another letter at most k times. Find the
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摘要：Given a string, find the length of the longest substring T that contains at most k distinct characters. For example, Given s = “eceba” and k = 2, T is
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摘要：Given a string, find the length of the longest substring without repeating characters. Examples: Given "abcabcbb", the answer is "abc", which the leng
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摘要：Given a string, find the length of the longest substring T that contains at most 2 distinct characters. For example, Given s = “eceba”, T is "ece" whi
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摘要：Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Remov
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摘要：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 num
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摘要：Given a binary array, find the maximum length of a contiguous subarray with equal number of 0 and 1. Example 1: Example 2: Note: The length of the giv
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摘要：Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2
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摘要：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 upd
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摘要：Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2
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摘要：Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. Example: Note: 本题比较简单，代码如下：
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摘要：Given an array nums and a target value k, find the maximum length of a subarray that sums to k. If there isn't one, return 0 instead. Note:The sum of
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摘要：You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a conca
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摘要：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 = "ADOBECOD
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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
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摘要：Suppose you are at a party with n people (labeled from 0 to n - 1) and among them, there may exist one celebrity. The definition of a celebrity is tha
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摘要：Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted i
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摘要：Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in each row are sorted f
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摘要：Follow up for "Remove Duplicates":What if duplicates are allowed at most twice? For example,Given sorted array nums = [1,1,1,2,2,3], Your function sho
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摘要：Given an array of scores that are non-negative integers. Player 1 picks one of the numbers from either end of the array followed by the player 2 and t
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摘要：In the "100 game," two players take turns adding, to a running total, any integer from 1..10. The player who first causes the running total to reach o
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摘要：You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take tu
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摘要：You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 ston
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摘要：You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take tu
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摘要：We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wron
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