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recursion.js
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recursion.js
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function iteratedFactorial(n) {
if (n < 0) {
return undefined;
}
if (n === 0) {
return 1;
}
let factor = 1;
for (let i = 1; i <= n; ++i) {
factor *= i;
}
return factor;
}
function recursedFactorial(n) {
if (n < 0) {
return undefined;
}
if (n === 0) {
return 1;
}
return n * recursedFactorial(n - 1);
}
function iteratedFibonacci(n) {
if (n === 0) {
return 0;
}
let a = 0;
let b = 1;
for (let i = 1; i < n; ++i) {
[a, b] = [b, a + b];
}
return b;
}
// TODO: redo this function using dynamic programming / memoization
function recursedFibonacci(n) {
if (n === 0) {
return 0;
}
if (n === 1) {
return 1;
}
return recursedFibonacci(n - 1) + recursedFibonacci(n - 2);
}
function iteratedReverseString(string) {
let reversedString = "";
for (let i = string.length - 1; i >= 0; --i) {
reversedString += string[i];
}
return reversedString;
}
function recursedReverseString(string) {
if (string.length <= 1) {
return string;
}
return recursedReverseString(string.substring(1)) + string[0];
}
export {
iteratedFactorial,
recursedFactorial,
iteratedFibonacci,
recursedFibonacci,
iteratedReverseString,
recursedReverseString,
};