One Pager Cheat Sheet

• Implement a function fibonacci(n) which returns the number in the Fibonacci sequence where n <= 40, with a time and space complexity of O(n).
• The Fibonacci sequence can be effectively generated using Recursion in order to efficiently calculate each successive number from the sum of the two prior.
• By storing intermediate results and using a recursive approach, the Fibonacci Sequence can be calculated with a complexity of `O($2^n$)$.
• We can memo-ize (store) previous function calls and their results by using the memoize function, which uses a hash map as a storage.
• To improve performance in recurring algorithms, use memoize to wrap the fibonacci function.

This is our final solution.

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}

var assert = require('assert');

​

/*

 * @param {number} n The Fibonacci number to get.

 * @returns {number} The nth Fibonacci number

 */

​

function fibonacci(num) {

  if (num < 0) throw 'num must be >= 0';

  if (num === 0) return 0;

  if (num === 1) return 1;

​

  return fibonacci(num - 1) + fibonacci(num - 2);

}

​

try {

  assert.equal(fibonacci(1), 1);

​

  console.log('PASSED: ' + '`fibonacci(1)` should return `1`');

} catch (err) {

  console.log(err);

}

​

try {

  assert.equal(fibonacci(17), 1597);

​

  console.log('PASSED: ' + '`fibonacci(17)` should return `1597`');

} catch (err) {

  console.log(err);

}

​

try {

You're doing a wonderful job. Keep going!

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