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Commit 30230dc

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Implemented recursive & iterative fibonacci (#9 IP)
1 parent 3dca3ce commit 30230dc

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7 files changed

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‎Algorithms/README.md

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# Algorithms
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## Core
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- [] Recursion
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- [X] Recursion
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- [ ] Dynamic Programming
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- [ ] Comparison Sorting
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- [ ] *Merge Sort*
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- [ ] Depth First Search (DFS)
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## Resources
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- [Visualizing Data Structures & Algorithms](https://visualgo.net/en)
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- [Visualizing Data Structures & Algorithms](https://visualgo.net/en)
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### Recursion
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- [Tail Call Optimization: ES6](https://2ality.com/2015/06/tail-call-optimization.html)

‎Algorithms/Recursion/Basics.ts

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function inception(repeat: number): string {
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// 1. Base Case(s)
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if (repeat === 0) return 'Done!\n'; // Base Case(s) must be written first in method
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// 2. Input Validation
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if (repeat < 1) return 'Too small!\n'; // Input validation must occur after base case(s)
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// 2?. Input Validation
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if (repeat < 1) return 'Too small!\n'; // Input validation should occur after base case(s)
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console.log('Counter:', repeat);
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‎Algorithms/Recursion/Fibonacci.ts

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// ---------------- Fibonacci Sequence ----------------
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// 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144...
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// Time Complexity: O(2^n) Space Complexity: O(2^n)
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function fibonacciRecursive(nthElement: number): number | any {
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// Base Cases
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if (nthElement === 1) return 0;
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if (nthElement === 2) return 1;
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//Input Validation
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if (nthElement < 1) return undefined;
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// Recursive Call: The nth element equals the sum of the previous 2 elements.
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return fibonacciRecursive(nthElement-2) + fibonacciRecursive(nthElement-1);
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}
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// Time Complexity: O(n) Space Complexity: O(1)
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function fibonacciIterative(nthElement: number): number | undefined {
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if (nthElement < 1) return undefined;
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else nthElement = Math.floor(nthElement);
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let previous = 0;
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let current = 1;
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if (nthElement === 1) return previous;
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if (nthElement === 2) return current;
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let fibonacci: number = 0;
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for (let i = 3; i <= nthElement; ++i) {
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fibonacci = previous + current;
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previous = current;
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current = fibonacci;
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}
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return fibonacci;
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}
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function validateFibonacciInput(nthElement: number) {
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return nthElement>0;
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}
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function printFibonacciIterative(nthElement: number) {
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console.log("Fibonacci Iterative", nthElement+':', fibonacciIterative(nthElement));
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}
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function printFibonacciRecursive(nthElement: number) {
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if(!validateFibonacciInput(nthElement)) {
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console.log("Input", nthElement, "is invalid -_-'");
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return;
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}
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console.log("Fibonacci Recursive", nthElement+':', fibonacciRecursive(nthElement));
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}
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//---------------------------------------------------------------------
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// ---------- MAIN PROGRAM ----------
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//---------------------------------------------------------------------
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if (import.meta.main) {
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console.log('------------ Iterative ------------');
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printFibonacciIterative(0);
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printFibonacciIterative(1);
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printFibonacciIterative(2);
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printFibonacciIterative(3);
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printFibonacciIterative(4);
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printFibonacciIterative(5);
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printFibonacciIterative(6);
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printFibonacciIterative(9);
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printFibonacciIterative(42);
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printFibonacciIterative(50);
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printFibonacciIterative(100);
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console.log('\n------------ Recursive ------------');
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printFibonacciRecursive(-1);
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printFibonacciRecursive(0);
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printFibonacciRecursive(1);
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printFibonacciRecursive(2);
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printFibonacciRecursive(3);
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printFibonacciRecursive(4);
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printFibonacciRecursive(5);
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printFibonacciRecursive(7);
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printFibonacciRecursive(8);
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printFibonacciRecursive(42); // Notice how much longer this takes than the iterative version
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// RUN: deno run Algorithms/Recursion/Fibonacci.ts
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}
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// --------------------------- Terminal Output: ---------------------------
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// ------------ Iterative ------------
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// Fibonacci Iterative 0: undefined
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// Fibonacci Iterative 1: 0
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// Fibonacci Iterative 2: 1
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// Fibonacci Iterative 3: 1
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// Fibonacci Iterative 4: 2
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// Fibonacci Iterative 5: 3
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// Fibonacci Iterative 6: 5
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// Fibonacci Iterative 9: 21
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// ------------ Recursive ------------
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// Input -1 is invalid -_-'
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// Input 0 is invalid -_-'
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// Fibonacci Recursive 1: 0
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// Fibonacci Recursive 2: 1
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// Fibonacci Recursive 3: 1
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// Fibonacci Recursive 4: 2
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// Fibonacci Recursive 5: 3
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// Fibonacci Recursive 7: 8
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// Fibonacci Recursive 8: 13

‎Playground/Challenges/Recursion/ReverseString.ts

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‎README.md

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- [X] Graphs
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### Algorithms
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- [] Recursion
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- [X] Recursion
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- [ ] Dynamic Programming
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- [ ] Comparison Sorting
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- [ ] *Merge Sort*

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