Algorithm problems in coding tests often evaluate theoretical knowledge and practical problem-solving skills that are frequently used in actual work. In this article, we will discuss the problem of finding the Kth number in an array. This problem requires techniques for sorting an array and extracting values from specific indices.<\/p>\n
Given an integer array Output the Kth number after sorting To solve this problem, we can proceed with the following steps:<\/p>\n There are several ways to sort an array. Common sorting algorithms include Quick Sort<\/strong>, Merge Sort<\/strong>, and Insertion Sort<\/strong>. However, using the built-in sorting function provided by Swift allows for convenient sorting.<\/p>\n To find the Kth number in the sorted array, we return the value at the K-1 index. If K exceeds the length of the array, we should return -1.<\/p>\narray<\/code> and an integer k<\/code>, write a function that returns the Kth number after sorting array<\/code> in ascending order. The Kth number uses 1-based indexing.<\/p>\nInput<\/h3>\n
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array<\/code>: An array containing integers, e.g., [3, 1, 2, 4, 5]<\/li>\nk<\/code>: A positive integer to find the Kth number in the array<\/li>\n<\/ul>\nOutput<\/h3>\n
array<\/code>. If K is greater than the length of the array, return -1.<\/p>\nExample<\/h3>\n
Input:\n array = [3, 5, 2, 1, 4]\n k = 3\n\n Output:\n 3\n <\/code><\/pre>\nSolution<\/h2>\n
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Step-by-step Solution<\/h3>\n
Step 1: Sorting the Array<\/h4>\n
Step 2: Finding the Kth Number<\/h4>\n
Swift Code Implementation<\/h3>\n
func findKthNumber(array: [Int], k: Int) -> Int {\n let sortedArray = array.sorted()\n guard k > 0 && k <= sortedArray.count else {\n return -1\n }\n return sortedArray[k - 1]\n }\n\n\/\/ Test\nlet array = [3, 5, 2, 1, 4]\nlet k = 3\nprint(findKthNumber(array: array, k: k)) \/\/ Output: 3\n <\/code><\/pre>\nComplexity Analysis<\/h2>\n