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摘要： Given a strings1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation... 阅读全文

摘要： 原题地址：https://oj.leetcode.com/problems/symmetric-tree/题意：判断二叉树是否为对称的。Given a binary tree, check whether it is a mirror of itself (ie, symmetric around ... 阅读全文

摘要： [leetcode] Latest added:2014-09-23Find the contiguous subarray within an array (containing at least one number) which has the largest product.For exam... 阅读全文

摘要： 原题地址：https://oj.leetcode.com/problems/surrounded-regions/题意：Given a 2D board containing'X'and'O', capture all regions surrounded by'X'.A region is cap... 阅读全文

摘要： 原题地址：https://oj.leetcode.com/problems/n-queens/题意：经典的N皇后问题。解题思路：这类型问题统称为递归回溯问题，也可以叫做对决策树的深度优先搜索（dfs）。N皇后问题有个技巧的关键在于棋盘的表示方法，这里使用一个数组就可以表达了。比如board=[1, ... 阅读全文

摘要： https://oj.leetcode.com/problems/combinations/Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.For example,If ... 阅读全文

摘要： 原题地址：https://oj.leetcode.com/problems/next-permutation/题意：Implement next permutation, which rearranges numbers into the lexicographically next greater... 阅读全文

摘要： Here is the basic algorithm about merge sort:def merge(s1,s2,s): i=j=0 while i + j 0 and A[j-1] > cur: # element A[j-1] must be after current ... 阅读全文

摘要： 题目： https://oj.leetcode.com/problems/integer-to-roman/Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from ... 阅读全文

摘要： 题目:https://oj.leetcode.com/problems/roman-to-integer/Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1... 阅读全文