Hello! Today, we will cover set problems that frequently appear in coding tests using Swift. A set is a data structure that collects non-duplicate elements and is useful for various problems. In this lecture, we will express sets and enhance our algorithmic thinking through problems utilizing them.<\/p>\n
Write a function that returns all unique numbers from a given integer array in the form of a set. In other words, it should remove any duplicate numbers contained in the input array and return a set of unique numbers.<\/p>\n
Input: [1, 2, 2, 3, 4, 4, 5]\nOutput: [1, 2, 3, 4, 5]<\/code><\/pre>\nConstraints<\/h3>\n\n- The length of the input array is between 1 and 10,000.<\/li>\n
- Numbers are between -1,000,000 and 1,000,000.<\/li>\n<\/ul>\n
Algorithm Approach<\/h2>\n
This problem can be solved with a simple approach as follows:<\/p>\n
\n- Utilize Swift’s Set to collect the input array and remove duplicates.<\/li>\n
- Add the elements of the array to the Set. Since a Set does not allow duplicate values, all duplicates will be removed automatically.<\/li>\n
- Finally, convert the Set back to an array and return the result.<\/li>\n<\/ol>\n
Swift Code Implementation<\/h3>\n
Below is the Swift code to solve the problem:<\/p>\n
func uniqueElements(from array: [Int]) -> [Int] {\n let uniqueSet = Set(array)\n return Array(uniqueSet)\n}\n\nlet inputArray = [1, 2, 2, 3, 4, 4, 5]\nlet result = uniqueElements(from: inputArray)\nprint(result) \/\/ [2, 3, 4, 5, 1]<\/code><\/pre>\nCode Explanation<\/h2>\n
Let’s take a closer look at the code above:<\/p>\n
\n- Define the function
uniqueElements(from:)<\/code>. This function takes an integer array as input and returns an array of unique elements.<\/li>\n- Call
Set(array)<\/code> to add all the elements of the input array to the set. During this process, duplicates are automatically removed due to the properties of Set.<\/li>\n- Convert the Set back to an array using
Array(uniqueSet)<\/code>. The final result will be an array consisting of distinct elements.<\/li>\n<\/ol>\nTest Cases<\/h3>\n
You can test the function above with various input values to verify its correct operation:<\/p>\n
print(uniqueElements(from: [1, 1, 1, 1])) \/\/ [1]\nprint(uniqueElements(from: [1, 2, 3, 3, 3, 2, 1])) \/\/ [1, 2, 3]\nprint(uniqueElements(from: [])) \/\/ []<\/code><\/pre>\nConclusion<\/h2>\n
In this lecture, we learned how to solve the problem of removing duplicate elements using Swift’s set. Sets enhance the conciseness of the code and help effectively manage duplicate data. I hope you practice using sets in various coding test problems to become a better programmer. Thank you!<\/p>\n
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