ykdojo

# Here is my Python implementation of the hash table data structure.
# And here's my video where I talk about it in depth: https://youtu.be/sfWyugl4JWA
class Hashtable:
    # Assumption: table_length is a prime number (for example, 5, 701, or 30011)
    def __init__(self, table_length):
        self.table = [None] * table_length
    
    ## An internal search function.
    # If it finds the given key in the table, it will return (True, index)
    # If not, it will return (False, the index where it would be inserted)

ykdojo

# My video where I talk about this data structure: https://youtu.be/sfWyugl4JWA

class Hashtable:
    # Assumption: table_length is a prime number (for example, 5, 701, or 30011)
    def __init__(self, table_length):
        self.table = [None] * table_length
    
    ## An internal search function.
    # If it finds the given key in the table, it will return (True, index)
    # If not, it will return (False, the index where it would be inserted)

ykdojo

class ST:
    def build(self, arr):
        max_len = 4 * len(arr)
        self.st = [None] * max_len
        self.arr_len = len(arr)
        self.helper(arr, 1, 0, len(arr) - 1)
    
    def helper(self, arr, v, l, r):
        if l == r:
            self.st[v] = arr[l]

ykdojo

/**
 * @param {number[]} A
 * @return {boolean}
 */
var validMountainArray = function(A) {
    if (A.length < 3) {
        return false;
    }
    let i = 0;
    let j = 1;

ykdojo

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var increasingTriplet = function(nums) {
    let currentMin = nums[0];
    let minWithSmaller = Infinity;
    
    for (let i = 1; i < nums.length; i++) {
        if (nums[i] > minWithSmaller) {

ykdojo

/**
 * @param {number[]} A
 * @return {boolean}
 */
var validMountainArray = function(A) {
    if (A.length < 3) {
        return false;
    }
    let current = A[0];
    let i = 1;

ykdojo

/**
 * @param {number[]} nums
 * @return {number}
 */
var rob = function(nums) {
    let memo = Array(nums.length);
    return helper(nums, 0, memo);
};

var helper = function(nums, current, memo) {

ykdojo

/**
 * @param {number[]} nums
 * @return {number}
 */
var rob = function(nums) {
    return helper(nums, 0);
};

var helper = function(nums, current) {
    if (current > nums.length) {

ykdojo

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {boolean}

ykdojo

var helper = function(current, last, target) {
    if (current == target) {
        return 0;
    } else if (current > target) {
        return Infinity;
    }
    
    let option1 = last != current ? helper(current, current, target) + 1 : Infinity;
    let option2 = last != 0 ? helper(current + last, last, target) + 1 : Infinity;
    if (option1 < option2) {