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Given an index k, return the kth row of the Pascal's triangle.For example, given k = 3,Return [1,3,3,1].Note:Could you optimize your algorithm to use only O(k) extra space?给定k，返回第k行的杨辉三角，最好使用O(k)的空间复杂...

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.Given linked list -- head = [4,5,1,9], which looks like following: 4 -> 5 -> 1 -&gt...

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between tw...

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 char...

Count the number of prime numbers less than a non-negative number, n.寻找n以内的素数个数。解法一最笨的方法是遍历到n，逐个判断，Python3代码如下：class Solution: def isPrime(self, a): if a <=1: retu...

Given an 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 using extra me...

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindro...

Say you have an array for which the ith element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one an...

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 (ie, buy one and sell one share of the stock), des...

Given two strings s and t , write a function to determine if t is an anagram of s.Example 1:Input: s = "anagram", t = "nagaram" Output: true Example 2:Input: s = "rat", t = "car" Output: false构建哈希表就可以...