l两周以来,第一次睡了个爽,开心! ================================= leetcode380 https://leetcode.com/problems/insert-delete-getrandom-o1/?tab=Description leetcode381 https://leetcode.com/problems/insert-delete-getrandom-o1-duplicates-allowed/ leetcode532 https://lee…

2017/11/22 Leetcode 日记 136. Single Number Given an array of integers, every element appears twice except for one. Find that single one. class Solution { public: int singleNumber(vector<int>& nums) { int len = nums.size(); ]; ; i < len; i++){…

2017/11/21 Leetcode 日记 496. Next Greater Element I You are given two arrays (without duplicates) nums1 and nums2 where nums1’s elements are subset of nums2. Find all the next greater numbers for nums1's elements in the corresponding places of nums2.…

2017/11/13 Leetcode 日记 463. 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/vertically (not diagonally). The grid is completely surro…

2017/11/14 Leetcode 日记 442. Find All Duplicates in an Array Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once. Find all the elements that appear twice in this array. Could you do it withou…

2017/11/9 Leetcode 日记 566. 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-dimensiona…

2017/11/7 Leetcode 日记 669. Trim a Binary Search Tree Given a binary search tree and the lowest and highest boundaries as L and R, trim the tree so that all its elements lies in [L, R] (R >= L). You might need to change the root of the tree, so the re…

2017/11/6 Leetcode 日记 344. Reverse String Write a function that takes a string as input and returns the string reversed. class Solution { public: string reverseString(string s) { , sz = s.size()-; ; i < sz; i++, sz--){ char temp = s[i]; s[i] = s[sz];…

2017/11/5 Leetcode 日记 476. Number Complement Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Note: The given integer is guaranteed to fit within the range of a 32-bit s…

2017/11/3 Leetcode 日记 654. Maximum Binary Tree Given an integer array with no duplicates. A maximum tree building on this array is defined as follow: The root is the maximum number in the array.(根节点是数组中的最大值) The left subtree is the maximum tree const…

380. Insert Delete GetRandom O(1) 实现插入.删除.获得随机数功能,且时间复杂度都在O(1).实际上在插入.删除两个功能中都包含了查找功能,当然查找也必须是O(1). 数组可以实现插入.删除.获得随机数O(1),但查找就不行了.(当然对于数组,直接删除的时间复杂度不是O(1),因为可能需要移动) hash.set都是红黑树实现的,查找.插入.删除的时间复杂度在O(logn). unordered_map.unordered_set是哈希表实现的,查找.插入.删除的…

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element fro…

380. Insert Delete GetRandom O(1) class RandomizedSet { ArrayList<Integer> nums; HashMap<Integer, Integer> locs; Random rand = new Random(); /** Initialize your data structure here. */ public RandomizedSet() { nums = new ArrayList<Integer&g…

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element fro…

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element fro…

380. Insert Delete GetRandom O(1) Add to List Description Submission Solutions Total Accepted: 21771 Total Submissions: 56175 Difficulty: Medium Contributors: Admin Design a data structure that supports all following operations in average O(1) time.…

1.题目描述 设计一个支持在平均 时间复杂度 O(1) 下,执行以下操作的数据结构. insert(val):当元素 val 不存在时,向集合中插入该项. remove(val):元素 val 存在时,从集合中移除该项. getRandom:随机返回现有集合中的一项.每个元素应该有相同的概率被返回 示例: // 初始化一个空的集合. RandomizedSet randomSet = new RandomizedSet(); // 向集合中插入 1 .返回 true 表示 1 被成功地插入. r…

380. 常数时间插入.删除和获取随机元素 设计一个支持在平均 时间复杂度 O(1) 下,执行以下操作的数据结构. insert(val):当元素 val 不存在时,向集合中插入该项. remove(val):元素 val 存在时,从集合中移除该项. getRandom:随机返回现有集合中的一项.每个元素应该有相同的概率被返回. 示例 : // 初始化一个空的集合. RandomizedSet randomSet = new RandomizedSet(); // 向集合中插入 1 .返回 tr…

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element fro…

题目: Design a data structure that supports all following operations in averageO(1) time. insert(val): Inserts an item val to the set if not already present. remove(val): Removes an item val from the set if present. getRandom: Returns a random element…

题目: Design a data structure that supports all following operations in average O(1) time.1.insert(val): Inserts an item val to the set if not already present.2.remove(val): Removes an item val from the set if present.3.getRandom: Returns a random elem…

Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an item val from the collection if present. getRandom:…

Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an item val from the collection if present. getRandom:…

题目: Design a data structure that supports all following operations in averageO(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an item val from the collection if present. getRand…

Design a data structure that supports all following operations in average O(1) time. Note: Duplicate elements are allowed. insert(val): Inserts an item val to the collection. remove(val): Removes an item val from the collection if present. getRandom:…

刷题备忘录,for bug-free leetcode 396. Rotate Function 题意: Given an array of integers A and let n to be its length. Assume Bk to be an array obtained by rotating the array A k positions clock-wise, we define a "rotation function" F on A as follow: F(k…

刷题备忘录,for bug-free 招行面试题--求无序数组最长连续序列的长度,这里连续指的是值连续--间隔为1,并不是数值的位置连续 问题: 给出一个未排序的整数数组,找出最长的连续元素序列的长度. 如: 给出[100, 4, 200, 1, 3, 2], 最长的连续元素序列是[1, 2, 3, 4].返回它的长度:4. 你的算法必须有O(n)的时间复杂度 . 解法: 初始思路 要找连续的元素,第一反应一般是先把数组排序.但悲剧的是题目中明确要求了O(n)的时间复杂度,要做一次排序,是不能达…

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剑指offer 重建二叉树 提交网址: http://www.nowcoder.com/practice/8a19cbe657394eeaac2f6ea9b0f6fcf6?tpId=13&tqId=11157 或 leetcode 105: https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/ 参与人数:5246  时间限制:1秒  空间限制:32768K 题目描述 输入某…

this blog from: http://blog.demofox.org/2017/03/09/how-to-train-neural-networks-with-backpropagation/ How to Train Neural Networks With Backpropagation Posted on March 9 2017 by Demofox This post is an attempt to demystify backpropagation, which is t…