Function climbStairs

javascript/0070-climbing-stairs.js:8–20

(n, index = 0)

 * @return {number}
 */
var climbStairs = (n, index = 0) => {
    const isBaseCase1 = n < index;
    if (isBaseCase1) return 0;

    const isBaseCase2 = index === n;
    if (isBaseCase2) return 1;

    const [next, nextNext] = [index + 1, index + 2];
    const left = climbStairs(n, next); /* Time O(2^N) | Space O(N) */
    const right = climbStairs(n, nextNext); /* Time O(2^N) | Space O(N) */

    return left + right;
};

/**
 * DP - Top Down