TheAlgorithms-Ruby/data_structures/arrays/richest_customer_wealth.rb

# 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 1: 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

#
# Approach 2: 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