HackerRank Python (Complete 115 Solutions) [33+ Hours]

Explore printing hello world in Python, using strings and variables, and practice a simple print statement with the sample output 'Hello world'; no input is required in this challenge.

Explore the hacker rank 'weird numbers' challenge in python, implementing conditional logic to print 'weird' for odd numbers and appropriate even-number ranges, with input handling.

Practice implementing simple arithmetic operations by reading two numbers and printing their sum, difference, and product while enforcing the one to ten to the power ten input range.

Practice implementing a division task by reading a and b, printing the integer part on the first line and the full decimal division on the second line without rounding.

Learn to implement a loop that reads a non-negative integer n and prints the squares of 0 through n-1, each on its own line, with input bounds 1 to 20.

implement a leap year function following the Gregorian rules: a year divisible by four is a leap year unless divisible by 100, unless divisible by 400, returning true or false.

Print numbers from 1 to n in Python using a for loop and the print function, avoiding string methods and enforcing 1 to 150 without spaces.

solve the hacker rank python runner up problem by reading a number and a space-separated list of scores, finding the maximum and the second maximum, and printing the runner-up score.

Learn list comprehension by generating all (x, y, z) triplets with x, y, z in 0..2 and filtering out x+y+z == 3, replacing nested loops with a concise final list.

Learn to work with nested lists in Python by extracting the names of students who have the second lowest score, including handling ties and sorting names alphabetically.

Learn to compute a student's percentage by averaging marks in Python, handle input for multiple students with a for loop, and format the result to two decimal places with constraints.

Master list manipulation in python by implementing append, insert, and print commands on a dynamic list, reading and executing commands, then printing results for each operation.

Explore tuples in python by learning how to store multiple items in one variable, understand that tuples are ordered and immutable, and access elements by indexing.

Swap the case of every letter in a string, turning lowercase to uppercase and vice versa, while leaving spaces and non-letter characters unchanged, within a length of 0 to 2000.

Explore how to split a string by a delimiter in Python and then join the pieces with a dash, turning the string into a list of substrings and back.

Practice reading a first name and last name, enforce a maximum length of ten for each, and print the names in the format 'first name last name' using string concatenation.

Learn to mutate a Python string by converting it to a list, changing a character by index, and joining back, with slicing as an alternative.

Count how many times a substring occurs in a string by scanning from left to right in Python, with input stripping and ASCII handling under given length constraints.

Learn python string validations by applying isalnum, isalpha, isdigit, islower, and isupper to detect alphanumeric, alphabetic, digits, and case. Handle line-by-line input under length constraints and output true or false.

Build a text wrap function to split a long string into lines of a max width and return a single string with newline breaks.

Explore solving the designer door mat puzzle by generating the m by n pattern with a center welcome, using Python input parsing, string multiplication, and looping to build the design.

master text alignment by implementing left, center, and right options for a string, filling in the blank code, and testing to match the target layout.

Solve a string formatting challenge by printing numbers from 1 to n in decimal, hexadecimal, and binary with proper padding and alignment in a single line.

Learn to capitalize names in Python for the HackerRank Capitalize challenge, handling first and last names, spaces, and multiple tokens with a robust string manipulation approach.

Explore how to generate the cartesian product using itertools.product, import the function, and implement a robust Python routine that prints all pairs from two input sequences in a space-separated format.

demonstrates generating all permutations of a list with itertools.permutations, optionally setting length, and printing each permutation in lexicographic (sorted) order by joining elements.

Learn to use collections.Counter in Python to count items, apply it to a shoe shop scenario, and compute revenue by matching sizes to customer offers.

Convert complex numbers into polar coordinates by computing the distance from the origin and the angle from the positive x-axis, using Python's complex type and printing results to three decimals.

Explore sets by removing duplicates, testing membership, and calculating the average of distinct heights by converting input to a set and printing the result to three decimal places.

Explore coding the alphabet rangoli by generating a size-based alphabet triangle, printing upper and lower halves with letters from a to z, using for loops and string operations in Python.

Explore how Python's defaultdict from the collections module provides a default value for missing keys, manage key-value pairs efficiently, and apply it to practice problems with dictionaries.

Learn to handle Python exceptions using try and except, managing zero division and value errors with multiple except blocks, and printing or handling errors effectively.

The minion game is described, with two players Stuart and Kevin building substrings from consonants and vowels respectively, scoring each substring occurrence to decide the winner.

Apply namedtuple to create lightweight student records, handle shuffled column orders, and compute average marks in a concise HackerRank Python challenge.

Explore how to use Python's calendar module to generate calendars and customize week start, then build a from-scratch day calculator with leap year rules and 400-year cycles.

Learn how to compute time delta by finding the absolute difference in seconds between two timestamps across time zones using Python, with hands-on examples from social media post times.

Learn to use Python's collections.OrderedDict to preserve first-seen item order while computing net prices for supermarket orders.

Learn to compute the symmetric difference of two sets in Python by parsing input, converting to integers, performing difference and union, and printing the sorted results one per line.

Learn how to use itertools.combinations to generate all k-length combinations from a sorted uppercase string, print them in lexicographic order, and handle Python input.

Learn how to use the set .add() operation to count distinct country stamps by adding each input to a set and returning the set's length.

Explore generating and printing all combinations with replacement using python's itertools, given an uppercase string and a length parameter, with sorted input and repeatable elements.

Learn to use the set union operation in Python to combine English and French newspaper subscribers and count the number of students with at least one subscription.

Master the set intersection operation in Python by using the ampersand operator to find common elements between two sets, then count the intersection size to solve a HackerRank challenge.

Explore Python set difference using dot and dash operators to subtract French subscribers from English newspaper subscribers and compute the total English subscribers.

Use the dot symmetric_difference operation on two sets A and B to get elements in either set but not both, illustrated with students subscribed to English or French newspapers.

Learn how to use the Python zip function to align scores across subjects, form tuples, and compute each student’s average score to one decimal place.

Learn to split a string of digits by multiple delimiters using re.split in Python, leveraging comma and dot with a character class pattern.

Learn to use map and lambda in Python to generate the first n Fibonacci numbers and print their cubes, with input validation for 0–15.

Learn the differences between set methods discard, remove, and pop, including their error behavior and return values, then apply a sequence of commands and sum the remaining elements.

Explore Python's collections.deque to perform double-ended queue operations—append, appendleft, extend, extendleft, pop, popleft, and rotate—through a hands-on puzzle-driven example.

Explore Python's eval built-in function to evaluate expressions from strings, including keywords, functions, and variables, with practical examples like nine plus five and real-world usage.

Learn to read a polynomial as a string, substitute a given x, evaluate p(x), and check if it equals k, with Python 2/3 input differences and integer constraints.

Check subset relations in python by validating that every element of the first set appears in the second, across multiple test cases, printing true or false.

Learn how to determine a strict superset by verifying a set contains all elements of each given subset and includes at least one extra element, across multiple cases.

Learn to perform set mutations in Python by applying update, intersection_update, difference_update, and symmetric_difference_update on sets, then compute and print the sum of the final elements.

Master arrays in Python by reversing a space separated input and converting elements to float with numpy, returning the reversed float array.

Learn to use shape and reshape to convert a space separated list of nine integers into a three across three matrix, creating a new shape without changing the original data.

Learn to transpose and flatten a matrix in Python by converting a 2d array into its transpose and a 1d flattened form, using space-separated input of n by m values.

Master the concatenate function for attaching arrays, from one-dimensional to multi-dimensional cases, and learn to specify the axis (default is the first dimension) for joining.

Learn to create multi-dimensional arrays of a given shape in Python, filled with zeros or ones, with explicit dtype handling and input parsing.

Generate an n by m identity-like matrix with a one on the main diagonal and zeros elsewhere, adjustable by a key to shift to the upper or lower diagonals.

Explore element-wise array mathematics in Python, performing A plus B, A minus B, A times B, A divided by B, A modulo B, A power B, and floor division.

Explore Python floor, ceil, and rint functions by applying them to a list of floating-point numbers and printing results in HackerRank style formatting.

Explore how to compute sums along a chosen axis and then multiply those sums to obtain a final product, using array inputs and axis zero handling.

Learn to compute minimum and maximum across multi-dimensional arrays by applying min along an axis (0 or 1) or none, then take the maximum of those results.

Compute mean along axis one, variance along axis zero, and standard deviation along axis for matrices in Python, with one-line expressions and practical input handling.

This lecture demonstrates calculating dot and cross products between vectors, explains their matrix representation for multi-dimensional arrays, and shows coding approaches to compute these operations using a tool.

Explore inner and outer products of vectors, generalizing the dot product in linear algebra, and learn to compute both results from given vector inputs.

Explore how polynomials are constructed from given roots to yield coefficients and how coefficients reveal roots, then learn to evaluate, differentiate, integrate, and fit polynomials using least-squares.

Solve linear algebra tasks using a number model to compute determinant, eigenvalues, eigenvectors, and matrix inverse from a square matrix; format results to two decimals.

Master how to calculate an XML document score in Python by counting attributes per element, traversing nested structures with an XML parser like elementary from root to leaves.

Learn to compute the maximum depth of nesting in an XML document using recursion and a global max depth, while counting child elements from input lines.

solve the captain's room puzzle by detecting the single captain's room number among room entries. use set to remove duplicates and compute captain's room via (sum(unique)*k - sum(all)) / (k-1).

Learn to compute division and modulus in Python with //, %, and divmod, by reading two integers and printing their integer division, modulo, and the divmod result.

Master exponentiation in Python by using the built-in power function and the three-argument pow with modulus, including handling negative exponents and modulus constraints.

Explore how Python handles arbitrarily large integers and rapid exponent growth by computing large power expressions with A, B, C, and D, illustrating no size limit unlike C++.

solve the no idea challenge by scanning an array against two disjoint sets, adding one for elements in A and subtracting one for elements in B, starting from zero.

Count word occurrences while preserving the order of first appearance, listing each distinct word with its frequency using a Python dictionary or defaultdict.

Learn to compress a string using run-length encoding by grouping consecutive characters with Python's groupby, producing counts followed by the corresponding character for each run.

Solve the piling up problem by greedily selecting cubes from either end to build a vertical tower, ensuring the bottom cube is at least as large as the one above.

Solve the triangle quest puzzle in Python by printing a triangle pattern with a single for loop and a print statement, using arithmetic operations on input n.

Learn to print a palindromic triangle of a given size using palindromic numbers derived from 11^k, producing sequences like 1, 11, 111, 121, and 12321.

Explore regular expressions, understand symbol meanings like digits and quantifiers, test patterns across multiple cases, and handle errors with try and except to validate expressions.

Learn to detect floating point numbers in strings using Python regular expressions, covering start conditions, exactly one dot, at least one decimal digit, and handling errors with try-except.

Learn to validate mobile numbers with regular expressions in Python by ensuring a ten-digit string starting with 7, 8, or 9, using pattern matching and test cases.

Validate roman numerals with regular expressions up to 3999, applying subtractive notation for four and nine, and map symbols M, D, C, L, X, V, I across thousands to units.

Debug the word score problem by fixing a bug in is_score_words to correctly count words with an even number of vowels and sum their scores using the provided template.

Identify the three most common lowercase characters in a string by counting occurrences, sorting by frequency in descending order, and breaking ties alphabetically; output the characters with their counts.

Sort athletes by a chosen attribute from the spreadsheet (age, height, weight) and, when attributes tie, preserve the order they appeared to produce a final ranked table.

Sort an alphanumeric string by grouping lowercase letters, then uppercase, then digits; within digits, place even digits before odd digits and sort each group.

Master iterables and iterators by solving a probability problem with Python's combinations, counting selections where at least one chosen element contains the letter a.

learn to use the reduce function with a lambda to multiply a list of rational numbers from left to right, optionally with an initial value, yielding a simplified numerator/denominator.

Explore regex substitution in Python by applying a function or lambda to each match to transform strings, including squaring numbers and replacing patterns, with careful handling of spaces and escapes.

Learn how default arguments in Python control function behavior when arguments are omitted, and how to debug state initialization in a stream-based function to produce correct odd or even sequences.

Validate credit card numbers by checking they start with 4, 5, or 6, contain 16 digits (0-9), may be hyphen-separated in groups of four, and forbid four consecutive repeated digits.

Learn to validate emails in Python using a filter with a custom validity function. The lecture explains username rules and extension constraints and shows lexical order sorting of valid emails.

Learn to validate a UID by enforcing ten alphanumeric characters, at least two uppercase letters, at least three digits, and no repetitions, using step-by-step Python techniques and regex patterns.

Explore re.findall and re.finditer to extract all non-overlapping and overlapping matches, compare their outputs, and learn lookahead tricks for handling overlaps while solving substring problems in Python.

Explore HTML basics and implement parsing with Python, building an HTML parser that identifies start and end tags, attributes, text, comments, and empty tags.

Detect html tags, start tags, attributes, and attribute values by parsing code lines and printing each tag with its attributes and values in the required format.

Identify valid hex color codes using six- or three-digit hexadecimal notation starting with #, and print each color in order of appearance while parsing CSS-like lines.

Validate and parse email addresses by enforcing username, domain, and extension formats, ensuring alphabetic starts and a 1-3 letter extension, then print names with valid emails in input order.

Split the string into three equal substrings of length k (k = len(s)/3). For each substring, keep the first occurrence of each character in order, then print the unique sequence.

Learn to validate postal codes with a regex approach in Python: enforce the 100000-299999 range and allow at most one alternating repetitive digit pair, using pattern matching instead of conditionals.

Decode the matrix script by reading columns left to right, top to bottom, extracting only alphanumeric characters and replacing inter-character symbols with a single space via regex substitution.

Compute the torsional angle between planes defined by points in 3D using dot and cross products, implemented in Python with a class structure and input coordinates.

Master implementing a complex number class to perform add, subtract, multiply, divide, and modulus, with precise three-decimal output and format rules across languages like C++ and Java.

Execute the maximize it problem by choosing one element from each list to maximize the sum of squares modulo m, exploring all combinations with Python.

Learn to standardize mobile numbers with decorators in Python, sort 10-digit numbers, and print them in the +91 two five-digit groups format using closures.

Learn to use decorators to build a name directory, print formatted names sorted by age and arrival order, and apply lambda and itemgetter for multi-parameter sorting.

Learn how any and all evaluate iterables in Python, returning true when any or all elements satisfy a condition, with examples on positive numbers and palindromic integers.

Explore Python regex with group(), groups(), and groupdict() to extract subpatterns and named groups, then find the first alphanumeric character with consecutive repetition from left to right.

Find angle MBC in a right triangle ABC with M as midpoint of AC using the law of cosines; convert to degrees and round to the nearest integer.

After completing 115 HackerRank Python questions, develop your own logic through brute practice, then expand to other sites and timed mocks to sharpen coding skills for company tests.

Develop rock, paper, scissors in Python by simulating you vs. the CPU with random choices, input validation, and a replay loop.