Merge branch 'master' into jk-shuffle-array

DIRECTORY.md

@@ -12,9 +12,11 @@
     * [Find The Highest Altitude](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/find_the_highest_altitude.rb)
     * [Fizz Buzz](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/fizz_buzz.rb)
     * [Get Products Of All Other Elements](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/get_products_of_all_other_elements.rb)
+    * [Jewels And Stones](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/jewels_and_stones.rb)
     * [Remove Elements](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/remove_elements.rb)
-    * [Shuffle Array](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/shuffle_array.rb)
+    * [Richest Customer Wealth](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/richest_customer_wealth.rb)
     * [Single Number](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/single_number.rb)
+    * [Shuffle Array](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/shuffle_array.rb)
     * [Sort Squares Of An Array](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/sort_squares_of_an_array.rb)
     * [Two Sum](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/two_sum.rb)
     * [Two Sum Ii](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/arrays/two_sum_ii.rb)
@@ -23,6 +25,8 @@
     * [Invert](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/binary_trees/invert.rb)
     * [Postorder Traversal](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/binary_trees/postorder_traversal.rb)
     * [Preorder Traversal](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/binary_trees/preorder_traversal.rb)
+  * Hash Table
+    * [Richest Customer Wealth](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/hash_table/richest_customer_wealth.rb)
   * Linked Lists
     * [Circular Linked List](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/linked_lists/circular_linked_list.rb)
     * [Doubly Linked List](https://github.com/TheAlgorithms/Ruby/blob/master/data_structures/linked_lists/doubly_linked_list.rb)
@@ -56,6 +60,7 @@
   * [Fibonacci](https://github.com/TheAlgorithms/Ruby/blob/master/maths/fibonacci.rb)
   * [Number Of Digits](https://github.com/TheAlgorithms/Ruby/blob/master/maths/number_of_digits.rb)
   * [Power Of Two](https://github.com/TheAlgorithms/Ruby/blob/master/maths/power_of_two.rb)
+  * [Prime Number](https://github.com/TheAlgorithms/Ruby/blob/master/maths/prime_number.rb)
   * [Square Root](https://github.com/TheAlgorithms/Ruby/blob/master/maths/square_root.rb)
   * [Square Root Test](https://github.com/TheAlgorithms/Ruby/blob/master/maths/square_root_test.rb)
   * [Sum Of Digits](https://github.com/TheAlgorithms/Ruby/blob/master/maths/sum_of_digits.rb)

data_structures/arrays/jewels_and_stones.rb

@@ -0,0 +1,86 @@
+# Challenge name: Jewels and Stones
+#
+# You're given strings jewels representing the types of stones that are jewels,
+# and stones representing the stones you have. Each character in stones is a type
+# of stone you have. You want to know how many of the stones you have are also
+# jewels.
+#
+# Letters are case sensitive, so "a" is considered a different type of stone from "A".
+#
+# Example 1:
+#
+# Input: jewels = "aA", stones = "aAAbbbb"
+# Output: 3
+#
+# Example 2:
+#
+# Input: jewels = "z", stones = "ZZ"
+# Output: 0
+#
+#
+# Constraints:
+#
+# 1 <= jewels.length, stones.length <= 50
+# jewels and stones consist of only English letters.
+# All the characters of jewels are unique.
+
+#
+# Approach 1: Brute Force
+#
+# Time Complexity: O(n^2)
+#
+
+def find_jewels(jewels, stones) 
+  jewels_array = jewels.split('')
+  stones_array = stones.split('')
+  result = 0
+  jewels_array.each do |jewel|
+    stones_array.each do |stone|
+      if jewel == stone
+        result += 1
+      end
+    end
+  end
+  result
+end
+
+puts find_jewels("aA", "aAAbbbb")
+# => 3
+puts find_jewels("z", "ZZ")
+# => 0
+
+#
+# Approach 2: Hash
+#
+# Time Complexity: O(n)
+#
+
+def find_jewels(jewels, stones)
+  jewels_array = jewels.split('')
+  stones_array = stones.split('')
+  result_hash = {}
+  result = 0
+
+  stones_array.each do |stone|
+    if result_hash[stone] 
+      result_hash[stone] += 1
+    else
+      result_hash[stone] = 1
+    end
+  end
+
+  jewels_array.each do |jewel|
+    if result_hash[jewel]
+      result += result_hash[jewel]
+    else
+      result
+    end
+  end
+
+  result
+end
+
+puts find_jewels("aA", "aAAbbbb")
+# => 3
+puts find_jewels("z", "ZZ")
+# => 0

data_structures/arrays/richest_customer_wealth.rb

@@ -0,0 +1,56 @@
+# Challenge name: Richest Customer Wealth
+#
+# You are given an m x n integer grid accounts where accounts[i][j]
+# is the amount of money the i​​​​​​​​​​​th​​​​ customer has in the j​​​​​​​​​​​th​​​​ bank.
+#
+# Return the wealth that the richest customer has.
+# A customer's wealth is the amount of money they have in all
+# their bank accounts. The richest customer is the customer that
+# has the maximum wealth.
+#
+# Example 1:
+# Input: accounts = [[1,2,3],[3,2,1]]
+# Output: 6
+# Explanation:
+# 1st customer has wealth = 1 + 2 + 3 = 6
+# 2nd customer has wealth = 3 + 2 + 1 = 6
+# Both customers are considered the richest with a wealth of 6
+# each, so return 6.
+#
+# Example 2:
+# Input: accounts = [[1,5],[7,3],[3,5]]
+# Output: 10
+# Explanation:
+# 1st customer has wealth = 6
+# 2nd customer has wealth = 10
+# 3rd customer has wealth = 8
+# The 2nd customer is the richest with a wealth of 10.
+#
+# Example 3:
+# Input: accounts = [[2,8,7],[7,1,3],[1,9,5]]
+# Output: 17
+
+#
+# Approach: Brute Force
+#
+# Time Complexity: O(n)
+#
+def find_richest_customer_wealth(accounts)
+  summed_accounts = []
+  accounts.each do |customer|
+    summed = 0
+    customer.each do |account|
+      summed += account
+    end
+    summed_accounts.push(summed)
+  end
+
+  summed_accounts.sort.pop()
+end
+
+puts find_richest_customer_wealth([[1,2,3],[3,2,1]])
+# => 6
+puts find_richest_customer_wealth([[1,5],[7,3],[3,5]])
+# => 10
+puts find_richest_customer_wealth([[2,8,7],[7,1,3],[1,9,5]])
+# => 17

data_structures/hash_table/richest_customer_wealth.rb

@@ -0,0 +1,59 @@
+# Challenge name: Richest Customer Wealth
+#
+# You are given an m x n integer grid accounts where accounts[i][j]
+# is the amount of money the i​​​​​​​​​​​th​​​​ customer has in the j​​​​​​​​​​​th​​​​ bank.
+#
+# Return the wealth that the richest customer has.
+# A customer's wealth is the amount of money they have in all
+# their bank accounts. The richest customer is the customer that
+# has the maximum wealth.
+#
+# Example 1:
+# Input: accounts = [[1,2,3],[3,2,1]]
+# Output: 6
+# Explanation:
+# 1st customer has wealth = 1 + 2 + 3 = 6
+# 2nd customer has wealth = 3 + 2 + 1 = 6
+# Both customers are considered the richest with a wealth of 6
+# each, so return 6.
+#
+# Example 2:
+# Input: accounts = [[1,5],[7,3],[3,5]]
+# Output: 10
+# Explanation:
+# 1st customer has wealth = 6
+# 2nd customer has wealth = 10
+# 3rd customer has wealth = 8
+# The 2nd customer is the richest with a wealth of 10.
+#
+# Example 3:
+# Input: accounts = [[2,8,7],[7,1,3],[1,9,5]]
+# Output: 17
+
+#
+# Approach: Hash
+#
+# Time Complexity: O(n)
+#
+def find_richest_customer_wealth(accounts)
+  result_hash = {}
+  accounts.each_with_index do |customer, i|
+    result_hash[i] = customer.sum
+  end
+
+  highest_value = 0
+  result_hash.each do |k, v|
+    if v > highest_value
+      highest_value = v
+    end
+  end
+
+  highest_value
+end
+
+puts find_richest_customer_wealth([[1,2,3],[3,2,1]])
+# => 6
+puts find_richest_customer_wealth([[1,5],[7,3],[3,5]])
+# => 10
+puts find_richest_customer_wealth([[2,8,7],[7,1,3],[1,9,5]])
+# => 17

maths/prime_number.rb

@@ -0,0 +1,34 @@
+# A ruby program to check a given number is prime or not
+# Mathematical explanation: A number which has only 2 factors i.e., 1 (one) and itself
+
+# Prime number check function
+def prime_number(number)
+  if number <= 1
+    non_prime_flag = true
+  elsif number == 2
+    non_prime_flag = false
+  elsif number % 2 == 0
+    non_prime_flag = true
+  else
+    non_prime_flag = (2..Math.sqrt(number)).any? { |i| number % i == 0 }
+  end
+
+  if !non_prime_flag
+    puts "The given number #{number} is a Prime."
+  else
+    puts "The given number #{number} is not a Prime."
+  end
+end
+
+# Non-prime input
+prime_number(1)
+
+# prime input
+# Number 2 is an even prime number
+prime_number(2)
+
+# Non-prime input
+prime_number(20)
+
+# Negative input
+prime_number(-21)