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摘要： We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wron 阅读全文

摘要： Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: [ 阅读全文

摘要： Given an integer, convert it to a roman numeral. 阅读全文

摘要： Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the 阅读全文

摘要： Reverse bits of a given 32 bits unsigned integer. For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), retur 阅读全文

摘要： Given the root of a tree, you are asked to find the most frequent subtree sum. The subtree sum of a node is defined as the sum of all the node values 阅读全文

摘要： Given a collection of intervals, merge all overlapping intervals. For example, Given [1,3],[2,6],[8,10],[15,18], return [1,6],[8,10],[15,18]. 思路： 首先，将 阅读全文

摘要： In LLP world, there is a hero called Teemo and his attacking can make his enemy Ashe be in poisoned condition. Now, given the Teemo's attacking ascend 阅读全文

摘要： You need to find the largest value in each row of a binary tree. Example: Input: 1 / \ 3 2 / \ \ 5 3 9 Output: [1, 3, 9] 思路： 层次遍历，每一层选出当前层最大值。 阅读全文

摘要： A sequence of number is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the 阅读全文