Recursion examples

org-tree-recursion.js

const organization = {name: "Zuckerberg", reports: [
	{name: "Schroepfer", reports:[
		{name:"Bosworth", reports: [
			{name:'Steve'},
			{name:'Kyle'},
			{name:'Andra', reports: [
				{name:'Amy'},
				{name:'Chuck'},
				{name:'Vinni'}
			]}
		]},
		{name:"Kirkland", reports: [
			{name:'Dom'},
			{name:'Keefer'},
			{name:'Maggie', reports: [
				{name:'Bryan'},
				{name:'Todd'},
				{name:'Dan'}
			]}
		]}			
	]},
	{name: "Warner", reports:[
		{name:"Denver", reports: [
			{name:'Dave'},
			{name:'Elizabeth'},
			{name:'Diane', reports: [
				{name:'Frank'},
				{name:'Stan'},
				{name:'Roy'}
			]}
		]},
		{name:"Jabobs", reports: [
			{name:'Nicholas'},
			{name:'Alicia'},
			{name:'Alexander', reports: [
				{name:'Jon'},
				{name:'William'},
				{name:'Paul'}
			]}
		]}			
	]}
]}

// ==============================
function traverse(indent, level) {
	level = level || 1;
	if (isArray(indent)) {
		traverseArray(indent, level);
	} else if ((typeof indent === 'object') && (indent !== null)) {
		traverseObject(indent, level);
	} else {
		console.log(" ".repeat(level), indent);
	}
}
 
function isArray(o) {
	return Object.prototype.toString.call(o) === '[object Array]';
}
 
function traverseArray(arr, level) {
	arr.forEach(function(indent) {
		traverse(indent, level + 1);
	});
}
 
function traverseObject(obj, level) {
	for (var key in obj) {
		if (obj.hasOwnProperty(key)) {
			traverse(obj[key], level + 1);
		}
	}
}

traverse(organization);

// ==============================
function printMixed (data, tab = 0) => {
	let spaces = '  '.repeat(tab);
	let string = spaces + data.name + '\n';
	if (!data.reports) {
		return string;
	} else {
		tab++;
		data.reports.forEach(report => {
			string += printMixed(report, tab);
		});
		return string;
	}
}
console.log(printMixed(organization))

recursion-iterator-compare.js

/** 
	7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040
	------------------
	7! = 7 x 6! = 5040
	6! = 6 x 5! = 720
	5! = 5 x 4! = 120
	4! = 4 x 3! = 24
	3! = 3 x 2! = 6
	2! = 2 x 1! = 2
	1! = 1 x 1 = 1
	0! = 1
**/

// Iteration
function factorialIter(num){
	var result = 1;
	for (var i = 1; i <= num; i++) {
		result = result * i;
	}
	return result;
}

// Accumulator - computes during stack push
function factorialAccumRecur(num, total = 1) {
	if (num === 0) {
		return total;
	}
	return factorialAccumRecur(num - 1, total * num);
}

// Tail Recursion - computes during stack pop
function factorialTailRecur(num) {
	if(num === 0) {
		return 1
	} else {
		return num * factorialTailRecur(num - 1);
	}

}

console.log('factorialIter:', factorialIter(100));

console.log('factorialAccumRecur:', factorialAccumRecur(100));

console.log('factorialTailRecur:', factorialTailRecur(100));

simple-org-tree-recursion

var organization = {
	"Zuckerberg": {		
		"Schroepfer": {
			"Bosworth": {
				"Steve":{},
				"Kyle":{},
				"Andra":{}
			},
			"Zhao": {
				"Richie":{},
				"Sofia":{},
				"Jen":{}
			},
			"Badros": {
				"John":{},
				"Mike":{},
				"Pat":{}
			},
			"Parikh": {
				"Zach":{},
				"Ryan":{},
				"Tes":{}
			}
		},
		"Schrage": {
			"VanDyck": {
				"Sabrina":{},
				"Michelle":{},
				"Josh":{}
			},
			"Swain": {
				"Blanch":{},
				"Tom":{},
				"Joe":{}
			},
			"Frankovsky": {
				"Jasee":{},
				"Brian":{},
				"Margaret":{}
			}
		},
		"Sandberg": {
			"Goler": {
				"Eddie":{},
				"Julie":{},
				"Annie":{}
			},
			"Hernandez": {
				"Rowi":{},
				"Inga":{},
				"Morgan":{}
			},
			"Moissinac": {
				"Amy":{},
				"Chuck":{},
				"Vinni":{}
			},
			"Kelley": {
				"Eric":{},
				"Ana":{},
				"Wes":{}
			}
}}};


function traverseA(data, depth = 0) {
	
	var indent = " ".repeat(depth * 4);

	Object.keys(data).forEach(key => {
		console.log(indent + key);
		traverseA(data[key], depth + 1)
	});
}

traverseA(organization)

function traverseB(node, indent) {
	indent = indent || 0;
	
	for (var key in node) {
		console.log(" ".repeat(indent), key);
		traverseB(node[key], indent + 4);
	}
}

traverseB(organization);