13.4 Recursive and Iterative Algorithms

Recursion vs. Iteration

Iterative algorithms generally perform faster and take less memory than their recursive counterparts. So what’s the advantage of recursion? Believe it or not, there are a lot of problems where a recursive solution is easier to write than an iterative one. Problems involving breaking a complex problem into pieces and then aggregating the results are perfect candidates for recursive solutions. For example, performing operations on a tree is much more intuitive than recursion. Additionally, recursive solutions can sometimes take less lines of code than their iterative counterparts.

Fibonacci Sequence Recursive


public static int fibonacciRecursion(int nthNumber) {
				// use recursion
				if (nthNumber == 0) {
							return 0;
				} else if (nthNumber == 1) {
							return 1;
				}
		return fibonacciRecursion(nthNumber - 1) + fibbonaciRecusion(nthNumber - 2);
	}

Fibonacci Sequence Iterative


public static int fibonacciLoop(int nthNumber) {
				//use loop
				int previouspreviousNumber, previousNumber = 0, currentNumber = 1;
				for (int = 1; i < nthNumber; i++) {
							previouspreviousNumber = previousNumber;
							previousNumber = currentNumber;
							currentNumber = previouspreviousNumber + previousNumber;
				}
				returns currentNumber;
		}

💻 Fibonacci.java

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13.3 Binary Search

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13.5 Converting Between Iterative and Recursive

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