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竖式问题：找出所有形如abc*de（三位数乘以两位数）的算式，使得在完整的竖式中，所有数字都属于一个特定的数字集合（也就是a b c d e 以及abc*e abc*d abc*de结果的每一位数字都属于一个集合）。下面你输入数字集合（相邻数字之间没有空格），输出所有竖式。每个竖式前应有编号，之后应有一个空行。最后输出解的总数，下面是输入输出样例（为了便于观察，竖式中的空格改用小数点显示，但所...

Say you have an array for which the ith element is the price of a given stock on day i.If you were only permitted to complete at most one transaction (i.e., buy one and sell one share of the stock),...

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.Note: For the purpose of this problem, we define empty string as valid palindrome.Examp...

Given a non-empty array of integers, every element appears twice except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without us...

Given an array, rotate the array to the right by k steps, where k is non-negative.Example 1:Input: [1,2,3,4,5,6,7] and k = 3Output: [5,6,7,1,2,3,4]Explanation:rotate 1 steps to the right: [7,1...

You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent house...

Write an algorithm to determine if a number is "happy".A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares o...

Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be replaced with another ...

Reverse a singly linked list.Example:Input: 1->2->3->4->5->NULLOutput: 5->4->3->2->1->NULLFollow up:A linked list can be reversed either iteratively or recursi...

sscanf函数：　   sscanf函数原型为int sscanf(const char *str, const char *format, ...)。将参数str的字符串根据参数format字符串来转换并格式化数据，转换后的结果存于对应的参数内。具体功能如下：（1）根据格式从字符串中提取数据。如从字符串中取出整数、浮点数和字符串等。（2）取指定长度的字符串...

LeetCode 225. Implement Stack using QueuesImplement the following operations of a stack using queues.push(x) -- Push element x onto stack. pop() -- Removes the element on top of the stack. top()...

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.Note: A leaf is a node with no children.Example:...

Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.Note: A leaf is a node with no childre...

Given a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as:a binary tree in which the depth of the two subtrees of every node never diff...

问题描述：考虑下面的01串序列：0,00,01,10,000,001,010,011,100,101,110,0000,0001，....，1101,1110,00000....首先是长度为1的 串，然后是长度为2的串，以此类推。如果看成二进制，相同长度的后一个串等于前一个串加1.上述序列不存在全为1的串。我们的任务是编写一个解码程序。首先输入一个编码头AB#TAN则根...

    假设有字符串s1和字符串s2，长度分别为n和m。在求解s2是否为s1的子串这个问题中，可称s1是匹配串，称s2为模式串。KMP算法是一个复杂度为O(n+m)的算法。    在KMP算法中，有很多定义next数组的方式，并文介绍其中一种。    next数组采用以下定义。若next[j]==k，则k满足以下条件的最大值；s2[0..k-1]与s2[j-k..j-1]相同，且s2[k]...

Given a 32-bit signed integer, reverse digits of an integer.Example 1:Input: 123Output: 321Example 2:Input: -123Output: -321Example 3:Input: 120Output: 21Note:Assume we are dea...

Given two binary strings, return their sum (also a binary string).The input strings are both non-empty and contains only characters 1 or 0.Example 1:Input: a = "11", b = "1"Output: "100"Exam...

Implement int sqrt(int x).Compute and return the square root of x, where x is guaranteed to be a non-negative integer.Since the return type is an integer, the decimal digits are truncated and only...

You are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?Note: Given n will be a positive...

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.Note:The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume tha...

Given two binary trees, write a function to check if they are the same or not.Two binary trees are considered the same if they are structurally identical and the nodes have the same value.Example ...

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For example:Given binary tree [3,9,20,null,null,15,7...

101. Symmetric Tree (对称二叉树)Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree [1,2,2,3,4,4,3] is symmetric: 1 / \...

Given a singly linked list, determine if it is a palindrome.Example 1:Input: 1->2Output: falseExample 2:Input: 1->2->2->1Output: trueFollow up:Could you do it in O(n) time a...