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recursion.js
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66 lines (61 loc) · 1.7 KB
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// Complete the following functions.
const nFibonacci = (n) => {
if (n < 0) {
console.log('Incorrect input');
} else if (n === 1) {
return 1;
} else if (n === 2) {
return 2;
} else {
return nFibonacci(n - 1) + nFibonacci(n - 2);
}
/*
f(5)
f(4) f(3)
f(3) f(2) f(2) f(1)
f(2) f(1)
*/
// fibonacci sequence: 1 2 3 5 8 13 ...
// return the nth number in the sequence
// The Fibonacci sequence is a series of numbers where a
// number is found by adding up the two numbers before it.
// Starting with 0 and 1, the sequence goes 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, and so forth.
// Written as a rule, the expression is xn = xn-1 + xn-2.
};
const nFactorial = (n) => {
if (n === 1) {
return 1;
}
return n * nFactorial(n - 1);
// factorial example: !5 = 5 * 4 * 3 * 2 * 1
// return the factorial of `n`
};
const checkMatchingLeaves = (obj, valueToCheck = null) => {
const arrayToCheck = Object.entries(obj);
// array
let checkValue = valueToCheck;
let foundBadValue = false;
arrayToCheck.forEach((element) => {
if (checkValue === null) {
checkValue = element[1];
} else if (typeof element[1] === 'object') {
const areMatching = checkMatchingLeaves(element[1], checkValue);
if (!areMatching) {
foundBadValue = true;
return;
}
} else if (checkValue !== element[1]) {
foundBadValue = true;
return;
}
});
return !foundBadValue;
// return true if every property on `obj` is the same
// otherwise return false
};
/* eslint-enable no-unused-vars */
module.exports = {
nFibonacci,
nFactorial,
checkMatchingLeaves
};