Coder|2015

1. Comparator 和 Comparable 相同的地方他们都是java的一个接口, 并且是用来对自定义的class比较大小的,什么是自定义class: 如 public class Person{ String name; int age }.当我们有这么一个personList,里面包含了person1, person2, persion3....., 我们用Collect

分析 原地算法 从后往前排序 即可 需要注意的异常: 把剩余的b元素 排入 a public void mergeSortedArray(int[] A, int m, int[] B, int n) { if (A == null || B == null) return; int index = m + n - 1; whil

Given a string and an offset, rotate string by offset. (rotate from left to right)Have you met this question in a real interview? Yes Example Given “abcdefg”.offset=0 => “abcdefg” offset=1 => “gabcd

学习格雷码 的规律“`java public class Solution {public ArrayList<Integer> grayCode(int n) { ArrayList<Integer> result = new ArrayList<Integer>(); for (int i = 0; i < Math.pow(2,n); ++i) { result.

Given a list of non negative integers, arrange them such that they form the largest number.Have you met this question in a real interview? Yes Example Given [1, 20, 23, 4, 8], the largest formed numb

哈夫曼(HUFFMAN)树和哈夫曼编码。哈夫曼编码是哈夫曼树的一个应用。哈夫曼编码应用广泛，如JPEG中就应用了哈夫曼编码。 首先介绍什么是哈夫曼树。哈夫曼树又称最优二叉树，是一种带权路径长度最短的二叉树。所谓树的带权路径长度，就是树中所有的叶结点的权值乘上其到根结点的 路径长度（若根结点为0层，叶结点到根结点的路径长度为叶结点的层数）。树的带权路径长度记为

Given number n. Print number from 1 to n. But:when number is divided by 3, print “fizz”. when number is divided by 5, print “buzz”. when number is divided by both 3 and 5, print “fizz buzz”. Have yo

Given an input string, reverse the string word by word.For example, Given s = “the sky is blue”, return “blue is sky the”.split ()函数分割public class Solution { public String reverseWords(String s)

Given 3*n + 1 numbers, every numbers occurs triple times except one, find it.Example Given [1,1,2,3,3,3,2,2,4,1] return 4Challenge One-pass, constant extra space.public class Solution { /**

Cosine similarity is a measure of similarity between two vectors of an inner product space that measures the cosine of the angle between them. The cosine of 0° is 1, and it is less than 1 for any other

For a given source string and a target string, you should output the first index(from 0) of target string in source string.If target does not exist in source, just return -1.Have you met this question

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.Have you met this question in a real interview? Yes Example “A man, a plan, a canal: Panam

分析统计词频即可以区分出两个字符串是否为变位词强制类型转换 为关键点charAt() 函数的使用…public class Solution { /** * @param s: The first string * @param b: The second string * @return true or false */ public b

Given two sorted integer arrays A and B, merge B into A as one sorted array.Example A = [1, 2, 3, empty, empty], B = [4, 5]After merge, A will be filled as [1, 2, 3, 4, 5]Note You may assume that A h

Given a binary tree, return the inorder traversal of its nodes’ values.Have you met this question in a real interview? Yes Example Given binary tree {1,#,2,3},1 \ 2 / 3return [1,3

Given a binary search tree and a new tree node, insert the node into the tree. You should keep the tree still be a valid binary search tree.Have you met this question in a real interview? Yes Example

Given a set of distinct integers, return all possible subsets.Have you met this question in a real interview? Yes Example If S = [1,2,3], a solution is:[ [3], [1], [2], [1,2,3], [1,3],

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.Have you met this question in a real interview? Yes Example For example, gi

Given a set of distinct integers, return all possible subsets.Have you met this question in a real interview? Yes Example If S = [1,2,3], a solution is:[ [3], [1], [2], [1,2,3], [1,3],

Find the number connected component in the undirected graph. Each node in the graph contains a label and a list of its neighbors. (a connected component (or just component) of an undirected graph is a

Compare two strings A and B, determine whether A contains all of the characters in B.The characters in string A and B are all Upper Case letters.Have you met this question in a real interview? Yes Exa

Given an array of strings, return all groups of strings that are anagrams.Have you met this question in a real interview? Yes Example Given [“lint”, “intl”, “inlt”, “code”], return [“lint”, “inlt”, “

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.Have you met this question in a real interview? Yes

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.The array may contain duplicates.Have you met this qu

最长回文子串暴力匹配public class Solution { /** * @param s input string * @return the longest palindromic substring */ public String longestPalindrome(String s) { // Write your cod

Write a method to replace all spaces in a string with %20. The string is given in a characters array, you can assume it has enough space for replacement and you are given the true length of the string.

Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length of last word in the string.If the last word does not exist, return 0.Example Given s = “Hello

The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, …1 is read off as “one 1” or 11.11 is read off as “two 1s” or 21.21 is read off as “one 2, then one

Given an array and a value, remove all occurrences of that value in place and return the new length.The order of elements can be changed, and the elements after the new length don’t matter.Have you met

Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length of last word in the string.If the last word does not exist, return 0.Example Given s = “Hello

Given an integer array, find a subarray where the sum of numbers is zero. Your code should return the index of the first number and the index of the last number.Example Given [-3, 1, 2, -3, 4], return

Given a rotated sorted array, recover it to sorted array in-place.Have you met this question in a real interview? Yes Example [4, 5, 1, 2, 3] -> [1, 2, 3, 4, 5]Challenge In-place, O(1) extra space a

Given an array nums of integers and an int k, partition the array (i.e move the elements in “nums”) such that:All elements < k are moved to the left All elements >= k are moved to the right Return th

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this in place with cons

Merge two given sorted integer array A and B into a new sorted integer array.Example A=[1,2,3,4]B=[2,4,5,6]return [1,2,2,3,4,4,5,6]class Solution { /** * @param A and B: sorted integer array

Given two 32-bit numbers, N and M, and two bit positions, i and j. Write a method to set all bits between i and j in N equal to M (e g , M becomes a substring of N located at i and starting at j)Have

Follow up for “Remove Duplicates”: What if duplicates are allowed at most twice?For example, Given sorted array A = [1,1,1,2,2,3],Your function should return length = 5, and A is now [1,1,2,2,3].publ

Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.You should preserve the original relative order of the nodes in each of the

Partition an integers array into odd number first and even number second.Example Given [1, 2, 3, 4], return [1, 3, 2, 4]Challenge Do it in-place.双指针public class Solution { /** * @param nums:

gray code is a binary numeral system where two successive values differ in only one bit. Given a non-negative integer n representing the total number of bits in the code, print the sequence of gray co