Renzhouzhou的博客

问题：https://leetcode.com/problems/isomorphic-strings/ 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 occu

问题：https://leetcode.com/problems/number-of-boomerangs/ Given n points in the plane that are all pairwise distinct, a “boomerang” is a tuple of points (i, j, k) such that the distance between i and j e

问题：https://leetcode.com/problems/happy-number/ 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,

问题：https://leetcode.com/problems/word-pattern/ Given a pattern and a string str, find if str follows the same pattern. Here follow means a full match, such that there is a bijection between a letter

问题：https://leetcode.com/problems/bulls-and-cows/ You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time

问题：https://leetcode.com/problems/single-number/ Given an array of integers, every element appears twice except for one. Find that single one. 分析：使用异或位运算符。相同为0，不同为1。如果有两个数均为5，它的的二进制均为0101，两者异或，0101^01

问题：https://leetcode.com/problems/valid-anagram/ Given two strings s and t, write a function to determine if t is an anagram of s. For example, s = “anagram”, t = “nagaram”, return true. s = “rat”,

问题：https://leetcode.com/problems/island-perimeter/ You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/v

问题：https://leetcode.com/problems/find-all-anagrams-in-a-string/ Given a string s and a non-empty string p, find all the start indices of p’s anagrams in s. Strings consists of lowercase English lette

问题：https://leetcode.com/problems/longest-palindrome/ Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built with those letters.

问题349：https://leetcode.com/problems/intersection-of-two-arrays/Given two arrays, write a function to compute their intersection.问题350：https://leetcode.com/problems/intersection-of-two-arrays-ii/

问题：https://leetcode.com/problems/count-primes/Countthe number of prime numbers less than a non-negative number, n.分析：埃拉托斯特尼筛法。找出所有的素数。素数最小是2，先把2以及2的倍数剔除去。再把3以及3的倍数剔除出去。注意三个小问题：(1)首先我们该用i*i代码：c

问题：https://leetcode.com/problems/valid-sudoku/ Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules. The Sudoku board could be partially filled, where empty cells are filled with