Restore IP Addresses

Given a string containing only digits, restore it by returning all possible valid IP address combinations.
（IP地址规则化）

Reverse Linked List II

Reverse a linked list from position m to n. Do it in one-pass.
（旋转link_list[m:n+1]）

Decode Ways

A message containing letters from A-Z is mapped to 1-26, Given a non-empty string containing only digits, determine the total number of ways to decode it.
（解码方法）

Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).
（列举所有子集）

Note: The solution set must not contain duplicate subsets.

Gray Code

The 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 code. A gray code sequence must begin with 0.
(n位格雷码)

Merge Sorted Array

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.
(合并有序数组)

Scramble String

Given two strings s1 and s2 of the same length, determine if s2 is a scrambled string of s1.
(判断一个字符串是否为另一个字符串“乱序”得到)

Partition List

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.
(切分链表)

Maximal Rectangle

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
(最大矩形)

Largest Rectangle in Histogram

Given n non-negative integers representing the histogram’s bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.
（在条形图中取最大矩形面积）