noc_lemontree的博客

在difficulty为easy的hash table部分，没有用到常见的哈希算法，更多的是借用数组的下标来实现。对于下标的操作看起来很简单，其实需要细致和耐心，可能一个小错误，比如下标字母弄错用成了上个循环使用的下标(t.t’),结束条件没写对等等就会导致错误。 A.在Valid Sudoku 中，判断中拓宽了思维，1。多动脑子，小九宫格中，将每个小个子的下标与第几个联系起来。2。对于一般的含有

【题目】 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 ano

【题目】 Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. Note: Try to come up as many solutions as you

【题目】 Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length. Do not allocate extra space for another array, you must do this in place w

【题目】 Count the number of prime numbers less than a non-negative number, n. Credits: Special thanks to @mithmatt for adding this problem and creating all test cases. 【题目分析】 这道题常用的判断一个数是否为质数是行不通的，根据

【题】 Given an integer, write a function to determine if it is a power of two. 【具体代码如下】 bool isPowerOfTwo(int n) { int i; if(n<1)return false; while(n!=1) { i=n%2; if(i=

【题目】Length of Last World Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length of last word in the string.If the last word does not exist, return 0.

【题目】 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”, t = “car”, return false.Note: You may assume

【题】 Determine whether an integer is a palindrome. Do this without extra space.【具体代码如下】bool isPalindrome(int x) { int stack[10]={-1}; if(x<0) return false; if(x==0)return true; int tmp;

题目：A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying to r

题目：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?题目分析：这也是一道简单而典型

【题目】 Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. Note: You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold ad

【题目】 Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. 【题目

【题目】 Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element

【题目】 Given a non-negative number represented as an array of digits, plus one to the number. The digits are stored such that the most significant digit is at the head of the list.【题目分析】 这道题的关键在于最高位有没

【题目】 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 the character ‘.’.Note: A valid Sudoku boar

【题目】 Given an array and a value, remove all instances of that value in place and return the new length. The order of elements can be changed. It doesn’t matter what you leave beyond the new length.【题

【题目】 Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly sin

【题目】 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 squa

【题目】 Roman to Integer Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.【题目分析】首先，罗马数字的表示必须要清楚，这一点上网查。【具体代码如下】int toNumber(char ch) {

【题目】 Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every eleme

[leetcode]Valid Palindrome解题报告 C语言Valid Palindrome Given a string,determine if it is a palindrome, considering only alphanumeric characters andignoring cases. For example, “A man, a plan,a canal: Pa

【题】 Reverse digits of an integer.Example1: x = 123, return 321 Example2: x = -123, return -321click to show spoilers. Have you thought about this? Here are some good questions to ask before coding.

题目：Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.分析：此题用递归的方式做非常简单，虽然一次性就通过