Plus One Given a non-negative number represented as an array of digits, plus one to the number. The digits are stored such that the most significant digit is at the head of the list. 思路:给定一个数组,表示一个数.然后返回+1的值.主要就是进位的问题.代码例如以下: public class Solution {…

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 two partitions. For example, Given 1->4->3->…

Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers 0, 1, and 2 to represent the color red, white, and bl…

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) must be in non-descending order. (ie, a ≤ b ≤ c) The…

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. Example 1: Given intervals [1,3],[6,9],…

Rotate List  Given a list, rotate the list to the right by k places, where k is non-negative. For example: Given 1->2->3->4->5->NULL and k = 2, return 4->5->1->2->3->NULL. 思路:题目非常清晰.思路是先得到链表长度.再从头開始直到特定点,開始变换连接就可以. 代码例如以下: /*…

Given two binary strings, return their sum (also a binary string). For example, a = "11" b = "1" Return "100". 思路:二进制加法,比較简单.代码例如以下: public class Solution { public String addBinary(String a, String b) { int len = Math.max(a.l…

Spiral Matrix Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order. For example, Given the following matrix: [  [ 1, 2, 3 ],  [ 4, 5, 6 ],  [ 7, 8, 9 ] ] You should return [1,2,3,6,9,8,7,4,5]. 思路:螺旋数…

Remove Element Given an array and a value, remove all instances of that value in place and return the new length. The order of elements can be changed. It doesn't matter what you leave beyond the new length. 思路:此题和26题一脉相承,算法上不难,详细如代码所看到的: public clas…

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], return 6. The above elevation ma…