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Suppose in a shoe shop there are n different shoes with different sizes present in an array called shoes and another list of pairs for m customers called demand is given, where demand[i] contains (shoe_size, money). A customer with demand i wants a shoe of size shoe_size and can pay the given amount of money. We need to find how much money the shopkeeper can earn by selling these shoes. Example If the input is shoes = [2, 3, 4, 5, 6, 8, 7, 6, 5, 18] and demand = [(6, 55), (6, 45), (6, 55), (4, 40), ... Read More
The Cartesian product of two lists creates all possible ordered pairs by combining each element from the first list with every element from the second list. Python provides multiple approaches to find the Cartesian product using itertools.product(), nested loops, or list comprehensions. Problem Understanding If we have two lists like [a, b] and [c, d], the Cartesian product will be [(a, c), (a, d), (b, c), (b, d)]. For input lists l1 = [1, 5, 6] and l2 = [1, 2, 9], the output should be all combinations of elements from both lists. Using itertools.product() The ... Read More
Let's understand the problem statement: we need to convert a given string to a title case, which involves capitalizing the first letter of each word while converting the remaining letters to lowercase. The following are the various ways to capitalize each word's first letter in a string ? Using title() method Using capitalize() method Using upper() method Importing string module Importing regex module Capitalizing a String in a File Using the title() ... Read More
A rangoli pattern is a diamond-shaped pattern that uses alphabets arranged symmetrically. Given a number n, we create an alphabet rangoli of size n where alphabets start from 'a' and go up to the nth letter of the alphabet. Understanding the Pattern For n = 5, the rangoli pattern looks like this: --------e-------- ------e-d-e------ ----e-d-c-d-e---- --e-d-c-b-c-d-e-- e-d-c-b-a-b-c-d-e --e-d-c-b-c-d-e-- ----e-d-c-d-e---- ------e-d-e------ --------e-------- The pattern has the following characteristics: Each row is symmetric with dashes for spacing The middle row contains all alphabets from 'a' to the nth letter Upper and lower halves mirror ... Read More
Sometimes we need to display numbers in different formats: decimal, octal, hexadecimal, and binary. Python provides format specifiers to convert numbers into these representations with proper alignment. So, if the input is like n = 10, then the output will be ? 1 1 1 1 2 2 2 10 3 3 3 11 4 4 4 100 5 5 5 101 6 6 ... Read More
A door mat pattern is a decorative text design that creates a symmetric mat-like structure. In this pattern, we use hyphens (-), dots (.), and pipe symbols (|) to create a design with "WELCOME" in the center. The mat has dimensions n × m, where m is a multiple of n. Understanding the Pattern The door mat follows this structure: Top half: Expanding pattern from 1 to n-1 (odd numbers only) Middle: "WELCOME" text surrounded by hyphens Bottom half: Mirror of the top half in reverse order Each row contains: Left padding of ... Read More
Text wrapping is a common task when formatting output for display or printing. Python's textwrap module provides the fill() function to wrap text into paragraphs with a specified width. Syntax textwrap.fill(text, width=70, **kwargs) Parameters The fill() function accepts the following parameters: text − The string to be wrapped width − Maximum line width (default is 70) break_long_words − Break words longer than width (default True) break_on_hyphens − Break on hyphens (default True) Basic Text Wrapping Let's wrap a text string with width 9 ? import textwrap ... Read More
A diamond pattern is a symmetric arrangement of asterisks that expands from one star to n stars, then contracts back to one star. The pattern consists of 2n-1 lines total, with the widest part containing n asterisks. Understanding the Pattern For n = 5, the diamond pattern looks like ? * * * * * * * * * * * * * * * * * * * * * * * * * ... Read More
When working with strings in Python, you may need to validate whether a string contains specific types of characters. This article demonstrates how to check if a string contains numbers, lowercase letters, and uppercase letters. Problem Statement Given a string, we need to check whether it contains all three of the following character types ? Numbers (digits) Lowercase letters Uppercase letters Note: The string may contain other symbols, but all three character types above must be present. For example, if the input string is "p25KDs", the output should be True because it contains ... Read More
This problem involves calculating the expected value of a function from indicator random variables based on local extrema in random permutations. Given values k and n, we work with a random permutation of first n natural numbers and calculate F = (X₂+...+Xₙ₋₁)ᵏ, where Xᵢ is 1 when pᵢ₋₁ < pᵢ > pᵢ₊₁ or pᵢ₋₁ > pᵢ < pᵢ₊₁ (local maximum or minimum), and 0 otherwise. Understanding the Problem The indicator random variable Xᵢ equals 1 when position i is a local extremum (peak or valley) in the permutation. The expected value calculation uses precomputed formulas for different values ... Read More