1 - 传RSA加密系统已被密码学大牛破解 - cracking-rsa.txt

近日，德国密码学家克劳斯·彼得·施诺尔（Claus Peter Schnorr）在预印本网站上传论文称自己破解了RSA加密系统。

　　此事引起密码学界和量子密码界的广泛关注。上海交通大学网络空间安全学院院长谷大武教授3月4日表示，昨天看到这个消息感到很吃惊。“如果属实，这个结果是很重要的，会对部分应用产生安全影响。我们在分析这篇文章，目前还没结论。”

　　RSA是1977年由罗纳德·李维斯特（Ron Rivest）、阿迪·萨莫尔（Adi Shamir）和伦纳德·阿德曼（Leonard Adleman）一起提出的加密算法。这一算法利用大素数分解困难的特性，由于大素数之积难被分解，因此该密码就难被破解。如果想要破解密码，就需要花费很长时间进行大量运算。
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Top | Category: Computing | Comments (0) | Tags: RSA, 密码学, 非对称加密算法, 破解, RSA, | 中文 | 1102 Views, 31471 Search Bots | 540 Characters

2 - Kaprekar - kaprekar.txt.txt

Hi, here's your problem today. This problem was recently asked by Facebook:

Kaprekar's Constant is the number 6174. This number is special because it has the property where for any 4-digit number that has 2 or more unique digits, if you repeatedly apply a certain function it always reaches the number 6174.

This certain function is as follows:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 868 Views, 20636 Search Bots | 134 Words

3 - Making a Height Balanced Binary Search Tree - making-a-height-balanced-binary-search-tree.txt.txt

Hi, here's your problem today. This problem was recently asked by Google:

Given a sorted list, create a height balanced binary search tree, meaning the height differences of each node can only differ by at most 1.

Here's some code to start with:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 397 Views, 23967 Search Bots | 104 Words

4 - Staying on a Chess Board - staying-on-a-chess-board.txt

Hi, here's your problem today. This problem was recently asked by Google:

A chess board is an 8x8 grid. Given a knight at any position (x, y) and a number of moves k, we want to figure out after k random moves by a knight, the probability that the knight will still be on the chessboard. Once the knight leaves the board it cannot move again and will be considered off the board.

Here's some starter code:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 409 Views, 24346 Search Bots | 94 Words

5 - Multitasking - multitasking.txt

Hi, here's your problem today. This problem was recently asked by AirBNB:

We have a list of tasks to perform, with a cooldown period. We can do multiple of these at the same time, but we cannot run the same task simultaneously.

Given a list of tasks, find how long it will take to complete the tasks in the order they are input.
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 925 Views, 22626 Search Bots | 77 Words

6 - Sort a Partially Sorted List - sort-a-partially-sorted-list.txt

Hi, here's your problem today. This problem was recently asked by Uber:

You are given a list of n numbers, where every number is at most k indexes away from its properly sorted index. Write a sorting algorithm (that will be given the number k) for this list that can solve this in O(n log k)

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 346 Views, 23401 Search Bots | 93 Words

7 - Most Frequent Subtree Sum - most-frequent-subtree-sum.txt

Hi, here's your problem today. This problem was recently asked by LinkedIn:

Given a binary tree, find the most frequent subtree sum.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 338 Views, 21116 Search Bots | 147 Words

8 - Fix Brackets - fix-brackets.txt

Hi, here's your problem today. This problem was recently asked by Twitter:

Given a string with only ( and ), find the minimum number of characters to add or subtract to fix the string such that the brackets are balanced.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 763 Views, 20806 Search Bots | 99 Words

9 - Palindrome Integers - palindrome-integers.txt

Hi, here's your problem today. This problem was recently asked by Twitter:

Given an integer, check if that integer is a palindrome. For this problem do not convert the integer to a string to check if it is a palindrome.

import math
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 354 Views, 22992 Search Bots | 57 Words

10 - Print a tree level-by-level, with line-breaks - print-a-tree-level-by-level,-with-line-breaks.txt

Hi, here's your problem today. This problem was recently asked by Apple:

You are given a tree, and your job is to print it level-by-level with linebreaks.

a
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 407 Views, 24189 Search Bots | 111 Words

11 - Spreadsheet Columns - spreadsheet-columns.txt

Hi, here's your problem today. This problem was recently asked by Apple:

In many spreadsheet applications, the columns are marked with letters. From the 1st to the 26th column the letters are A to Z. Then starting from the 27th column it uses AA, AB, ..., ZZ, AAA, etc.

Given a number n, find the n-th column name.
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 3344 Views, 24615 Search Bots | 80 Words

12 - Generate All IP Addresses - generate-all-ip-addresses.txt

i, here's your problem today. This problem was recently asked by Microsoft:

An IP Address is in the format of A.B.C.D, where A, B, C, D are all integers between 0 to 255.

Given a string of numbers, return the possible IP addresses you can make with that string by splitting into 4 parts of A, B, C, D.
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 288 Views, 22621 Search Bots | 99 Words

13 - Consecutive Ones - consecutive-ones.txt

Hi, here's your problem today. This problem was recently asked by Microsoft:

Return the longest run of 1s for a given integer n's binary representation.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 437 Views, 20424 Search Bots | 52 Words

14 - Spreadsheet Column Title - spreadsheet-column-title.txt.txt

Hi, here's your problem today. This problem was recently asked by Amazon:

MS Excel column titles have the following pattern: A, B, C, ..., Z, AA, AB, ..., AZ, BA, BB, ..., ZZ, AAA, AAB, ... etc. In other words, column 1 is named "A", column 2 is "B", column 26 is "Z", column 27 is "AA" and so forth. Given a positive integer, find its corresponding column name.
Examples:
Input: 26
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 285 Views, 23083 Search Bots | 116 Words

15 - Compare Version Numbers - compare-version-numbers.txt

Hi, here's your problem today. This problem was recently asked by Amazon:

Version numbers are strings that are used to identify unique states of software products. A version number is in the format a.b.c.d. and so on where a, b, etc. are numeric strings separated by dots. These generally represent a hierarchy from major to minor changes. Given two version numbers version1 and version2, conclude which is the latest version number. Your code should do the following:
If version1 > version2 return 1.
If version1 < version2 return -1.
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 317 Views, 21481 Search Bots | 192 Words

16 - Reverse a Directed Graph - reverse-a-directed-graph.txt

Hi, here's your problem today. This problem was recently asked by Facebook:

Given a directed graph, reverse the directed graph so all directed edges are reversed.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 336 Views, 22011 Search Bots | 115 Words

17 - Absolute Path - absolute-path.txt

Hi, here's your problem today. This problem was recently asked by Facebook:

Given a file path with folder names, '..' (Parent directory), and '.' (Current directory), return the shortest possible file path (Eliminate all the '..' and '.').

Example
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18 - Design Tic-Tac-Toe - design-tic-tac-toe.txt

Hi, here's your problem today. This problem was recently asked by Google:

Design a Tic-Tac-Toe game played between two players on an n x n grid. A move is guaranteed to be valid, and a valid move is one placed on an empty block in the grid. A player who succeeds in placing n of their marks in a horizontal, diagonal, or vertical row wins the game. Once a winning condition is reached, the game ends and no more moves are allowed. Below is an example game which ends in a winning condition:

Given n = 3, assume that player 1 is "X" and player 2 is "O"
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 409 Views, 19474 Search Bots | 261 Words

19 - Top K Frequent words - top-k-frequent-words.txt

Hi, here's your problem today. This problem was recently asked by AirBNB:

Given a non-empty list of words, return the k most frequent words. The output should be sorted from highest to lowest frequency, and if two words have the same frequency, the word with lower alphabetical order comes first. Input will contain only lower-case letters.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 318 Views, 19671 Search Bots | 102 Words

20 - Detect Linked List Cycle - detect-linked-list-cycle.txt

Hi, here's your problem today. This problem was recently asked by Uber:

Given a linked list, determine if the linked list has a cycle in it. For notation purposes, we use an integer pos which represents the zero-indexed position where the tail connects to.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 265 Views, 21927 Search Bots | 120 Words

21 - Plus One - plus-one.txt

Hi, here's your problem today. This problem was recently asked by LinkedIn:

Given a non-empty array where each element represents a digit of a non-negative integer, add one to the integer. The most significant digit is at the front of the array and each element in the array contains only one digit. Furthermore, the integer does not have leading zeros, except in the case of the number '0'.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 1133 Views, 20419 Search Bots | 90 Words

22 - Find Missing Numbers in an Array - find-missing-numbers-in-an-array.txt

Hi, here's your problem today. This problem was recently asked by Twitter:

Given an array of integers of size n, where all elements are between 1 and n inclusive, find all of the elements of [1, n] that do not appear in the array. Some numbers may appear more than once.

Example:
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Top | Category: Computing | Comments (0) | Tags: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | English | 227 Views, 20417 Search Bots | 84 Words