Compute the sum of digits of a two-digit number by converting it to a string, splitting into digits, and reducing them to the total.

Learn to find all longest strings in an array in two passes: first compute the maximum length, then collect strings that match that length.

Explore how to verify an alphabet subsequence by converting a string to characters, extracting ASCII codes, using a set to detect duplicates, and checking for increasing order.

Compute the maximal adjacent difference in an array by tracking absolute differences of neighboring elements using Math.abs, iterating through the array, and updating the max difference.

Learn to implement the array previous less algorithm: for each position, find the nearest previous value smaller than the current, or output -1 if none, using backward loops and shifting.

Iterate through the input array to replace each occurrence of the target element with a substitute, returning the modified array.

Sort the array, compute the largest value plus one, and test jump distances up to that limit using modulo checks to avoid obstacles and count valid touches.

This lecture explains a boolean algorithm to determine if a bishop can hit a pawn on a chessboard by mapping letters to numbers and comparing coordinate sums, reflecting same-color squares.

Compute the century from a four-digit year by applying floor(year/100) and adjusting for exact multiples of 100, with edge cases shown by 1005 yielding 20 and 1700 yielding 17.

Parse a single input that may be a character or a numeric string. Determine parity for numbers and return not a digit when the input is not a number.

Compute the bot's answers by averaging the times of trainer responses that were correct. Return 0 if no correct answers exist, and learn to process training data and task results.

Explore crossing sum, a multi-dimensional array algorithm that sums the cross area in a two-dimensional matrix by iterating a row and column and using reduce.

Count the number of different symbols in a string by turning it into a character array and collecting unique chars with includes and push, then return the length.

Compute a factorial by initializing total to 1 and multiplying by each i from 1 to n, then return the accumulated product.

Learn how to extract the left most digit from a string by building a 0–9 digits array, splitting the input into characters, and returning the match with a for loop.

Monitor a growing plant that grows by the up speed each day and loses height by the down speed at night, then compute the days to reach the desired height.

Implement a password lockout algorithm that locks the account after more than ten consecutive failed attempts, resets the counter on a correct entry, and signals lockout by returning true.

Convert a number to a fixed-width string by chopping digits when width is smaller, padding with leading zeros when wider, covering three edge cases and refactoring.

Learn how to extract the file ids for changes with a later backup time, using iteration, removing duplicates, and sorting for a clean result.

Validate the launch sequence by tracking each system's previous step in an object, using hasOwnProperty, and ensure each subsequent step increases; return true or false accordingly.

Compute how many page numbers can be printed from the current page with given ink. Convert numbers to strings to count digits, updating the current page, and return last page.

Develop pro categorization by building a triple nested array that maps each profession to its matching professionals based on preferences, using a double nested loop, hasOwnProperty, lowercasing, and sorting.

Compute each pro's average rating from a 1–5 scale and compare it to a configurable threshold. Return the indices of those below the threshold for manual review.

Learn to reflect a string by mapping each lowercase character to its opposite on the alphabet using a reflection dictionary, iterating characters, and concatenating the results.

Model the theater as a grid with x and y coordinates to count interrupted seats. Multiply (columns minus current column plus one) by (rows minus current row).

Learn strings construction by counting character frequencies and calculating how many times string a can be formed from string b with alphabet counts, floor division, and missing character checks.

Learn to sum all prime numbers with a nested loop algorithm, starting at two, verifying primality and updating a running total of positive primes.

Compute the sum of all odd Fibonacci numbers up to a given input by iterating Fibonacci numbers with three variables: previous, current, and result, updating them as you go.

Construct a square digits sequence by splitting numbers into digits, squaring them, summing, and iterating until a duplicate appears, counting iterations for the 100 algorithms challenge.

Determine if one value from array one and one from array two can sum to 42 by building a hash map of needed differences and checking each element.

Organize tasks into today, upcoming, and later using array destructuring and a day-based deadline rubric, classifying values by exact day and within a week.

Explore how closure in JavaScript captures variables from a parent function and returns a function that retains access. See a counter that increments across calls, showing persistent state without globals.

Explain the difference between double equals and triple equals in JavaScript, where double equals checks value and triple equals checks value and type. Use a string five versus number five.

Explore how strict mode in JavaScript enforces stricter rules by placing 'use strict' at the top of a file to prevent accidental global variables, aided by linters.