Cracking the iOS Interview: Key Coding Challenges

Explore alternative solutions to detect duplicate characters by comparing sets and arrays, counting with loops, and using Swift methods like contains and append.

Explore how to check if two strings have the same characters, using a set and sorting. See a loop-based alternative with a guard statement to verify each character.

Learn to count character occurrences in a string for iOS interview prep, implementing both a loop-based solution and a functional reduce approach, as a string extension.

Remove extra spaces from a sentence by using a string extension with components, filtering out empty items, and joining the results; alternatively, build a loop to accumulate nonempty items.

Learn to determine if a string is a pangram by lowercasing, filtering non alphabet characters, and confirming all 26 letters appear, using a string extension and a boolean result.

Learn to implement a Swift string extension that returns a tuple with counts of vowels and consonants, using lowercase normalization and character sets, demonstrated with examples.

Define a function to compare two strings for differences by more than three characters, ensure equal length, iterate side by side, count mismatches, and return true if differences exceed three.

Find the longest common prefix across an array of strings. Start with the first element, extend the prefix, and use hasPrefix checks.

Learn to reverse the characters of a string while keeping word order by splitting into words, reversing each character sequence, and joining back using a string extension.

Sort an array of strings by length using a collection extension, and implement it with self.sorted by count to order names by character length.

Implement a Swift extension on collection to fetch the index of a given element by iterating with enumerated and returning the offset, or nil if not found.

Learn higher order functions like reduce, max, min, filter, sort, map, and compact map, and see how one-line expressions can replace loops for clearer, potentially faster code.

Explore higher order functions in depth by using max, min, filter, sort, map, and compactMap to transform arrays, cast values, and handle nils, building blocks for upcoming coding challenges.

Learn to implement a recursive function that generates permutations of a string, with a base case when count is zero and a for loop to build each permutation.

Learn run length encoding by implementing a string extension that compresses consecutive identical characters into a character and its count, building the output through iteration.

Create our own power function by multiplying the number by itself the required number of times in a loop, and verify with 5 to the 3rd power.

Explore how to implement an isPrime function in Swift by extending Int, using modulus checks to determine prime numbers, and returning a boolean.

Explore multiple Swift techniques to determine if a string is numeric, including character checks, higher-order functions, and type casting, with examples like 123 versus 13D.

Extend string functionality with an extension to sum digits by filtering digits 0 to 9 and using guard let for safe unwrapping, plus reduce for a cleaner approach.

Count how many times a specific digit appears in an array by mapping numbers to strings and reducing the results using a collection extension for integers.

Explore building a custom min function with for loops to find the lowest value in a numeric list, without using built-in min or max helpers, handling optional values.

Filter a collection to keep even values and reduce them to a total. Practice using filter and reduce to sum even integers.

Explore control structures in Swift by working through an integer array, using if statements and contains checks on targets, and switch cases with defaults, while printing results to the screen.

Explore loops in iOS coding by comparing for loops, while loops, and enumerated iterations, and learn to count occurrences with dictionaries, use stride for stepping, and leverage enums with CaseIterable.

Explore how the ternary operator compares to if statements, and learn to combine conditions with or and and operators to build simple control structures.

Explore how time complexity and benchmarking reveal a function's efficiency, from constant time (O(1)) to linear and logarithmic scales, and compare memory use through space complexity.