摘要：
Follow up for "Remove Duplicates":
What if duplicates are allowed at most twice? 阅读全文
摘要：
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 neighboring. The same letter cell may not be used more than once. 阅读全文
摘要：
Given a set of distinct integers, nums, return all possible subsets.
Note: The solution set must not contain duplicate subsets. 阅读全文
摘要：
Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. 阅读全文
摘要：
随手搜的一个问题，本来只是想印证一下自己的想法，怎料这个问题居然还有这么多不同的说法。 阅读全文
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). 阅读全文