Yeffry's public fiddles
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k6jgLb74
No-Library (pure JS), HTML, CSS, JavaScript
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firstDuplicate
Note: Write a solution with O(n) time complexity and O(1) additional space complexity, since this is what you would be asked to do during a real interview. Given an array a that contains only numbers in the range from 1 to a.length, find the first duplicate number for which the second occurrence has the minimal index. In other words, if there are more than 1 duplicated numbers, return the number for which the second occurrence has a smaller index than the second occurrence of the other number does. If there are no such elements, return -1. Example For a = [2, 3, 3, 1, 5, 2], the output should be firstDuplicate(a) = 3. There are 2 duplicates: numbers 2 and 3. The second occurrence of 3 has a smaller index than than second occurrence of 2 does, so the answer is 3. For a = [2, 4, 3, 5, 1], the output should be firstDuplicate(a) = -1. Input/Output [execution time limit] 4 seconds (js) [input] array.integer a Guaranteed constraints: 1 ≤ a.length ≤ 105, 1 ≤ a[i] ≤ a.length. [output] integer The element in a that occurs in the array more than once and has the minimal index for its second occurrence. If there are no such elements, return -1. [JavaScript (ES6)] Syntax Tips // Prints help message to the console // Returns a string function helloWorld(name) { console.log("This prints to the console when you Run Tests"); return "Hello, " + name; }