Algorithm's Exercises

Algorithm's exercises on Python with doctests. Some tasks were taken from the LeetCode.

• 01.py - Get prime numbers in interval.

• 02.py - Get sequences with numbers and operators ('+' or '-'), where result equals the certain sum.

• 03.py - Check number on primary.

• 04.py - Convert greek number to arabic number.

• 05.py - Reverse 2 variables without third.

• 06.py - Convert string to Haffman's code through tree.

• 07.py - Convert Haffman's code to string.

• 08.py - Realizing of max-heap.

• 09.py - Given:

  • integer number n (where 1 ≤ n ≤ 10^5);

  • array A[1…n] (where 1 ≤ A[i] ≤ 10^9);

  • integer number k (where 1 ≤ k ≤ 10^5);

  • array B[1…k](where 1 ≤ B[j] ≤ 10^9).
    For each item in B there should print an index i( where 1 ≤ i ≤ n) for A[i]=B[j], else to print -1 if this item does not exist.

    Sample Input:
    5 1 5 8 12 13
    5 8 1 23 1 11
    
    Sample Output:
    3 1 -1 1 -1
    

• 10.py - n natural numbers (where 1 ≤ n ≤ 10^4 and every number ≤ 10) are given. Algorithm must print increasing sequence.

• 11.py - Script must read text data and print n max numbers from it. Script has to perform extra conditions: • number is any digits sequence;
  • number can include max 1000 digits;
  • script should get only 1 param - n;
  • it must have tests;
  • text data(file) may be very big (before 40Gb!).

• 12.py - Script must check string with brackets on correctness. There are 3 different ways(functions) for checking. If string is correct - function returns 'Success' else position(start from = 1(!)) with symbol which breaks sequence. Examples:

Input         =>   Output
"({([])})"    =>   'Success'
"()[]}"       =>       5
"[]([]"       =>       3
"{*}"         =>   'Success'

• 13.py - Two int numbers ('n','m') are given. If anyone divides to another - print '1' otherwise '0'. Attention! Conditions and loops ('if', 'while') are banned!

• 14.py - Collection of commands are given (correct sequence of commands are guaranteed). Function adds/removes int numbers in stack and control max value with access O(1). Type of commands: 'push ' - add to stack, 'pop' - remove from stack, 'max' - just print max.

• 15.py - By the number 'n' (1≤n≤10^9) find max number 'k', which allows to set 'n' like a sum of 'k' different(!) summands. Function must return array of summands(where len(summands)==k).

• 16.py - Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

• 17.py - Given an integer x, return true if x is a palindrome, and false otherwise without(!) converting the integer to a string.

• 18.py - Given two strings s and t, return true if t is an anagram of s, and false otherwise.

• 19.py - Given an integer array nums, move all 0's to the end of it while maintaining the relative order of the non-zero elements.

• 20.py - Given two strings s and goal, return true if you can swap two letters in s so the result is equal to goal, otherwise, return false.

• 21.py - An array is monotonic if it is either monotone increasing or monotone decreasing. An array nums is monotone increasing if for all i <= j, nums[i] <= nums[j]. An array nums is monotone decreasing if for all i <= j, nums[i] >= nums[j]. Given an integer array nums, return true if the given array is monotonic, or false otherwise.

• 22.py - You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a LINKED LIST(!). You may assume the two numbers do not contain any leading zero, except the number 0 itself.

• 23.py - Given a string s, find the length of the longest substring without repeating characters.