解法专题
力扣刷题 杨辉三角（使用c++ vector解法）
杨辉三角 题目描述示例1示例2提示:代码 题目描述 给定一个非负整数 numRows，生成「杨辉三角」的前 numRows 行。 在「杨辉三角」中，每个数是它左上方和右上方的数的和。 示例1 输入: numRows = 5 输出: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]] 示例2 输入: numRows = 1
【java编程（在线笔试）】【链表】两道k个一组翻转链表题目（包含非递归和递归两种解法）
一、给你一个链表，每 k 个节点一组进行翻转，请你返回翻转后的链表。如果节点总数不是 k 的整数倍，那么请将最后剩余的节点也翻转顺序。 1. 非递归解法 /*** Definition for singly-linked list.* public class ListNode {* int val;* ListNode next;* ListNode(int x) {
每天刷个算法题20160525：快速排序的递归转非递归解法
版权所有。所有权利保留。 欢迎转载，转载时请注明出处： http://blog.csdn.net/xiaofei_it/article/details/51524798 为了防止思维僵化，每天刷个算法题。已经刷了几天了，现在发点代码。 我已经建了一个开源项目，每天的题目都在里面： https://github.com/Xiaofei-it/Algorithms
每天刷个算法题20160524：阿克曼函数的递归转非递归解法
版权所有。所有权利保留。 欢迎转载，转载时请注明出处： http://blog.csdn.net/xiaofei_it/article/details/51524754 为了防止思维僵化，每天刷个
LeetCode第21题之Generate Parentheses（两种解法）
C++代码： 解法一（在LeetCode上运行效率高于解法二）： #include <vector>#include <iostream>#include <string>using namespace std;class Solution {private:vector<string> res;public: //leftRemain保存还可以放左括号的数目，rightRemain
3Sum Closest问题及解法
问题描述： Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have
Longest Common Prefix问题及解法
问题描述： Write a function to find the longest common prefix string amongst an array of strings. 问题分析： 我们只需要从头到尾把每个字符串共同的字符前缀找出即可。 详见代码： class Solution {public:string longestCommonPrefix(vec
Roman to Integer问题及解法
问题描述： Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. 问题分析： 我们根据罗马数的特点，从后往前循环字符串，若i代表的值小于i+1代表的值，sum值减小，否则就增加。 详见代码： class Solutio
Integer to Roman问题及解法
问题描述： Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 问题分析： 本题目目的是将一个整数转换为罗马数字的表现形式。我们可以将能用的到罗马数字存到数组里，然后再调用。 详见代码： class Solut
Container With Most Water问题及解法
问题描述： Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Fi
Regular Expression Matching问题及解法
问题描述： Implement regular expression matching with support for '.' and '*'. 示例： '.' Matches any single character.'*' Matches zero or more of the preceding element.The matching should cover the ent
Palindrome Number问题及解法
问题描述： Determine whether an integer is a palindrome. Do this without extra space. 求解一个数是不是回文数。 问题求解思路： 1.负数不是回文数 2.回文数正着读和反着读一样，故可将该数反转与原数比较大小 我的代码如下： class Solution {public:bool isPali
String to Integer (atoi)问题及解法
问题描述： Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible i
ZigZag Conversion题目及解法
问题描述： The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) P A H NA P
Reverse Integer问题及解法
问题描述： Reverse digits of an integer. 示例： Example1: x = 123, return 321 Example2: x = -123, return -321 话不多说，代码很清楚 class Solution {public:int reverse(int x) {long long rev = 0;while(x != 0){r
Valid Anagram问题及解法
问题描述： 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 a
Add Digits问题及解法
问题描述： Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. 示例： Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit
Ugly Number问题及解法
问题描述： 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
Delete Node in a Linked List问题及解法
问题描述： Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node wit
Binary Tree Paths问题及解法
问题分析： Given a binary tree, return all root-to-leaf paths. 示例： given the following binary tree: 1/ \2 3\5 All root-to-leaf paths are: ["1->2->5", "1->3"] 问题分析： 这里涉及到将整数转换为字符串的问题，还好新
Implement Queue using Stacks问题及解法
问题描述： Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue.pop() -- Removes the element from in front of queue.peek() -- Get the front element
Power of Two问题及解法
问题描述： Given an integer, write a function to determine if it is a power of two. 问题分析： 每一个2的幂，都是大于0的整数，且转换成二进制时，里面1的个数只有一个。 过程详见代码： class Solution {public:bool isPowerOfTwo(int n) {int cou
Invert Binary Tree问题及解法
问题描述： Invert a binary tree. 4/ \2 7/ \ / \1 3 6 9to 4/ \7 2/ \ / \9 6 3 1 过程详见代码： /*** Definition for a binary tree node.* struct TreeNode {* int val;
Contains Duplicate II问题及解法
问题描述： 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 absolute difference between i and j is at m
Reshape the Matrix问题及解法
问题描述： In MATLAB, there is a very useful function called 'reshape', which can reshape a matrix into a new one with different size but keep its original data. You're given a matrix represented by a