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原创 C++探讨一: 函数返回值为类对象和类对象引用

C++ 中函数返回值为类对象的研究

2023-06-22 17:40:04 6422 5

原创 Shortest Unsorted Continuous Subarray

Given an integer array, you need to find one continuous subarray that if you only sort this subarray in ascending order, then the whole array will be sorted in ascending order, too.You need to find the

2017-06-07 14:20:40 298

原创 Can Place Flowers

Suppose you have a long flowerbed in which some of the plots are planted and some are not. However, flowers cannot be planted in adjacent plots - they would compete for water and both would die.Given a

2017-06-05 22:22:17 320

原创二分法（查找元素及其上界与下界）

利用二分法去查找某个元素效率高，将所要查找的元素称为key，有时利用二分法进行查找key的上界与下界，下界通常为key第一次出现的位置，上界通常为第一个大于key的位置。1 寻找元素的代码：int find(int array[], int len,int key) { int left = 0, right = len ; // attention while (left

2017-06-04 15:42:41 1302 1

原创 [Array]Triangle

Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.For example, given the following triangle [ [2], [3,4], [6,5,

2017-05-20 21:03:10 254

原创 Find Minimum in Rotated Sorted Array

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).Find the minimum element.You may assume no duplicate exist

2017-05-06 22:27:28 167

原创 Find Peak Element

A peak element is an element that is greater than its neighbors.Given an input array where num[i] ≠ num[i+1], find a peak element and return its index.The array may contain multiple peaks, in that case

2017-05-06 21:52:01 155

原创 Minimum Size Subarray Sum

Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn’t one, return 0 instead.For example, given the array

2017-05-06 20:19:13 177

原创 3Sum

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note: The solution set must not contain duplic

2017-05-04 21:11:58 149

原创 3Sum Closest

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 exactly

2017-05-04 20:56:08 158

原创 vector中size问题

首先看一段代码： vector<int> a{1,2,3}; cout << a.size() << endl; vector<int> b{}; cout << b.size() << endl; cout << a.size() - 3 << endl; cout << b.size() - 3 << endl;程序运行结果：可以发现 b.size

2017-05-04 15:22:32 3401

原创 4Sum

Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target.Note: The solution set mu

2017-05-04 15:06:15 160

原创 Permutations II

Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example, [1,1,2] have the following unique permutations: [ [1,1,2], [1,2,1], [2,1,1]

2017-05-04 11:04:04 160

原创 Permutations

Given a collection of distinct numbers, return all possible permutations.For example, [1,2,3] have the following permutations: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1]

2017-05-04 10:49:08 164

原创 Next Permutation

Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers.If such arrangement is not possible, it must rearrange it as the lowest possible orde

2017-05-04 10:21:50 183

原创 Combination Sum III

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers.Example 1:Input: k = 3, n =

2017-05-04 09:00:07 188

原创 Combination Sum

Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen from C

2017-05-04 08:49:23 158

原创 Combination Sum II

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.Each number in C may only be used once in the combination.No

2017-05-04 08:41:24 132

原创 Linked List Cycle II

Given a linked list, return the node where the cycle begins. If there is no cycle, return null.Note: Do not modify the linked list.Follow up: Can you solve it without using extra space?方法：寻找进入环的第一个节点。

2017-05-03 17:13:31 143

原创 Find the Duplicate Number

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, fin

2017-05-03 17:03:36 158

原创 Game of Life

According to the Wikipedia’s article: “The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970.”Given a board with m by n ce

2017-05-03 09:41:56 156

原创 Spiral Matrix

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.For example, Given the following matrix:[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ] ] You sh

2017-05-03 08:57:03 168

原创 First Unique Character in a String

Given a string, find the first non-repeating character in it and return it’s index. If it doesn’t exist, return -1.Examples:s = “leetcode” return 0.s = “loveleetcode”, return 2. Note: You may assume

2017-05-02 20:34:26 142

原创 Relative Ranks

Given scores of N athletes, find their relative ranks and the people with the top three highest scores, who will be awarded medals: “Gold Medal”, “Silver Medal” and “Bronze Medal”.Example 1: Input: [5

2017-05-02 20:21:20 201

原创 Construct the Rectangle

For a web developer, it is very important to know how to design a web page’s size. So, given a specific rectangular web page’s area, your job by now is to design a rectangular web page, whose length L

2017-05-02 20:18:46 156

原创 Base 7

Given an integer, return its base 7 string representation.Example 1: Input: 100 Output: “202” Example 2: Input: -7 Output: “-10” Note: The input will be in range of [-1e7, 1e7].class Solution {p

2017-05-02 14:06:32 187

原创 Reshape the Matrix

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 two-dimensio

2017-05-02 14:00:13 453

原创 Array Partition I

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), …, (an, bn) which makes sum of min(ai, bi) for all i from 1 to n as large as possibl

2017-05-02 12:09:07 237

原创 Fizz Buzz

Write a program that outputs the string representation of numbers from 1 to n.But for multiples of three it should output “Fizz” instead of the number and for the multiples of five output “Buzz”. For n

2017-05-02 11:46:30 193

原创 Minimum Absolute Difference in BST

Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.Example:Input:1 \ 3 / 2Output: 1Explanation: The minimum

2017-05-02 11:29:12 163

原创 Symmetric Tree

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 / \ 2 2 / \ / \ 3 4 4 3 But the

2017-05-02 10:14:10 147

原创 Minimum Depth of Binary Tree

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.方法：前序遍历，注意代码简洁度。自己写的/** * Definition fo

2017-05-02 09:23:06 156

原创 Binary Tree Level Order Traversal II

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],

2017-05-01 17:34:01 130

原创 Diameter of Binary Tree

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may no

2017-05-01 17:00:58 177

原创 Balanced Binary Tree

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 differ by

2017-05-01 16:43:49 163

原创 Path Sum

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.For example: Given the below binary tree and sum = 2

2017-05-01 16:13:06 154

原创 Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.For example, given the following binary tree:1 / \ 2 3 \ 5 All root-to-leaf paths are:[“1->2->5”, “1->3”]方法：注意to_string的用法。/** * Defi

2017-05-01 16:02:42 133

原创 Sum of Left Leaves

Find the sum of all left leaves in a given binary tree.Example:3 / \ 9 20 / \ 15 7There are two left leaves in the binary tree, with values 9 and 15 respectively. Return 24.方法：树的结构

2017-05-01 15:35:10 177

原创 Path Sum III

You are given a binary tree in which each node contains an integer value.Find the number of paths that sum to a given value.The path does not need to start or end at the root or a leaf, but it must go

2017-05-01 15:09:53 163

Concurrent C++ local code

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