Hello! Today, I will conduct a coding test lecture for developers preparing for job applications using Swift. The topic of this session is Greatest Common Divisor (GCD)<\/strong>. The greatest common divisor is the largest number among the common divisors of two numbers and is used in various algorithm problems in addition to its mathematical concept.<\/p>\n Write a function in Swift that finds the greatest common divisor of the given two integers There are various methods to find the greatest common divisor, but the most commonly used method is the Euclidean algorithm. This algorithm is based on the following two simple facts:<\/p>\n Based on the two principles above, I will explain step by step how to apply the Euclidean algorithm to find the greatest common divisor.<\/p>\n First, define a function that takes two integers and returns the greatest common divisor. The function signature is as follows:<\/p>\n Inside the function, check if both input values are 0. In this case, return the message ‘undefined’:<\/p>\n Use the Euclidean algorithm to iteratively calculate the greatest common divisor. In this process, swap the two numbers and use the remainder to update the values:<\/p>\n Integrating all the steps above, we can complete the final greatest common divisor function:<\/p>\n Now, let\u2019s validate the greatest common divisor function we have written with various test cases. Below are some example test cases:<\/p>\n In this lecture, we covered an algorithm problem to find the greatest common divisor using Swift. We were able to write concise and efficient code following the principles of the Euclidean algorithm. Algorithm problems can be further developed through understanding mathematical principles and practicing implementing them in programming. We will continue to conduct coding test lectures on various topics, so please stay tuned!<\/p>\nProblem Description<\/h2>\n
a<\/code> and b<\/code>. Additionally, if both numbers are 0, it should output a message saying ‘undefined’.<\/p>\nfunc gcd(_ a: Int, _ b: Int) -> String<\/code><\/pre>\nProblem-Solving Approach<\/h2>\n
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a<\/code> and b<\/code> is gcd(a, 0) = |a|<\/code>.<\/li>\na<\/code> and b<\/code> is gcd(a, b) = gcd(b, a % b)<\/code>.<\/li>\n<\/ul>\nImplementation of the Euclidean Algorithm<\/h3>\n
Step 1: Function Definition<\/h4>\n
func gcd(_ a: Int, _ b: Int) -> String<\/code><\/pre>\nStep 2: Input Validation<\/h4>\n
if a == 0 && b == 0 {\n return \"undefined\"\n }<\/code><\/pre>\nStep 3: Algorithm Implementation<\/h4>\n
var a = abs(a)\n var b = abs(b)\n\n while b != 0 {\n let temp = b\n b = a % b\n a = temp\n }\n return String(a)<\/code><\/pre>\nStep 4: Completing the Full Code<\/h4>\n
func gcd(_ a: Int, _ b: Int) -> String {\n if a == 0 && b == 0 {\n return \"undefined\"\n }\n var a = abs(a)\n var b = abs(b)\n\n while b != 0 {\n let temp = b\n b = a % b\n a = temp\n }\n return String(a)\n }<\/code><\/pre>\nTest Cases<\/h2>\n
print(gcd(48, 18)) \/\/ Output: 6\nprint(gcd(0, 0)) \/\/ Output: undefined\nprint(gcd(56, 98)) \/\/ Output: 14<\/code><\/pre>\nConclusion<\/h2>\n