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1716. Calculate Money in Leetcode Bank
1903. Largest Odd Number in String

Author: remy727

README.md

@@ -394,6 +394,7 @@
 | 1688 | Count of Matches in Tournament | [Ruby](./algorithms/ruby/1688-count-of-matches-in-tournament.rb) | Easy |
 | 1697 | Checking Existence of Edge Length Limited Paths | [Ruby](./algorithms/ruby/1697-checking-existence-of-edge-length-limited-paths.rb) | Hard |
 | 1706 | Where Will the Ball Fall | [Ruby](./algorithms/ruby/1706-where-will-the-ball-fall.rb) | Medium |
+| 1716 | Calculate Money in Leetcode Bank | [Ruby](./algorithms/ruby/1716-calculate-money-in-leetcode-bank.rb) | Easy |
 | 1721 | Swapping Nodes in a Linked List | [Ruby](./algorithms/ruby/1721-swapping-nodes-in-a-linked-list.rb) | Medium |
 | 1727 | Largest Submatrix With Rearrangements | [Ruby](./algorithms/ruby/1727-largest-submatrix-with-rearrangements.rb) | Medium |
 | 1732 | Find the Highest Altitude | [Ruby](./algorithms/ruby/1732-find-the-highest-altitude.rb) | Easy |
@@ -413,6 +414,7 @@
 | 1870 | Minimum Speed to Arrive on Time | [Ruby](./algorithms/ruby/1870-minimum-speed-to-arrive-on-time.rb) | Medium |
 | 1877 | Minimize Maximum Pair Sum in Array | [Ruby](./algorithms/ruby/1877-minimize-maximum-pair-sum-in-array.rb) | Medium |
 | 1887 | Minimize Maximum Pair Sum in Array | [Ruby](./algorithms/ruby/1887-reduction-operations-to-make-the-array-elements-equal.rb) | Medium |
+| 1903 | Largest Odd Number in String | [Ruby](./algorithms/ruby/1903-largest-odd-number-in-string.rb) | Easy |
 | 1921 | Eliminate Maximum Number of Monsters | [Ruby](./algorithms/ruby/1921-eliminate-maximum-number-of-monsters.rb) | Medium |
 | 1926 | Nearest Exit from Entrance in Maze | [Ruby](./algorithms/ruby/1926-nearest-exit-from-entrance-in-maze.rb) | Medium |
 | 1930 | Unique Length-3 Palindromic Subsequences | [Ruby](./algorithms/ruby/1930-unique-length-3-palindromic-subsequences.rb) | Medium |

algorithms/ruby/1716-calculate-money-in-leetcode-bank.rb

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+# frozen_string_literal: true
+
+# 1716. Calculate Money in Leetcode Bank
+# Easy
+# https://leetcode.com/problems/calculate-money-in-leetcode-bank
+
+=begin
+Hercy wants to save money for his first car. He puts money in the Leetcode bank every day.
+He starts by putting in $1 on Monday, the first day. Every day from Tuesday to Sunday, he will put in $1 more than the day before. On every subsequent Monday, he will put in $1 more than the previous Monday.
+Given n, return the total amount of money he will have in the Leetcode bank at the end of the nth day.
+
+Example 1:
+Input: n = 4
+Output: 10
+Explanation: After the 4th day, the total is 1 + 2 + 3 + 4 = 10.
+
+Example 2:
+Input: n = 10
+Output: 37
+Explanation: After the 10th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4) = 37. Notice that on the 2nd Monday, Hercy only puts in $2.
+
+Example 3:
+Input: n = 20
+Output: 96
+Explanation: After the 20th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4 + 5 + 6 + 7 + 8) + (3 + 4 + 5 + 6 + 7 + 8) = 96.
+
+Constraints:
+1 <= n <= 1000
+=end
+
+# @param {Integer} n
+# @return {Integer}
+def total_money(n)
+  k, x = n / 7, n % 7
+  (7 * k * (k + 7) / 2) + (x * (2 * k + x + 1) / 2)
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_total_money < Test::Unit::TestCase
+  def test_
+    assert_equal 10, total_money(4)
+    assert_equal 37, total_money(10)
+    assert_equal 96, total_money(20)
+  end
+end

algorithms/ruby/1903-largest-odd-number-in-string.rb

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+# frozen_string_literal: true
+
+# 1903. Largest Odd Number in String
+# Easy
+# https://leetcode.com/problems/largest-odd-number-in-string
+
+=begin
+You are given a string num, representing a large integer. Return the largest-valued odd integer (as a string) that is a non-empty substring of num, or an empty string "" if no odd integer exists.
+A substring is a contiguous sequence of characters within a string.
+
+Example 1:
+Input: num = "52"
+Output: "5"
+Explanation: The only non-empty substrings are "5", "2", and "52". "5" is the only odd number.
+
+Example 2:
+Input: num = "4206"
+Output: ""
+Explanation: There are no odd numbers in "4206".
+
+Example 3:
+Input: num = "35427"
+Output: "35427"
+Explanation: "35427" is already an odd number.
+
+Constraints:
+1 <= num.length <= 105
+num only consists of digits and does not contain any leading zeros.
+=end
+
+# @param {String} num
+# @return {String}
+def largest_odd_number(num)
+  i = num.length - 1
+  while i >= 0
+    case num[i]
+    when "1", "3", "5", "7", "9" then return num[0..i]
+    end
+    i -= 1
+  end
+
+  ""
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_largest_odd_number < Test::Unit::TestCase
+  def test_
+    assert_equal "5", largest_odd_number("52")
+    assert_equal "", largest_odd_number("4206")
+    assert_equal "35427", largest_odd_number("35427")
+  end
+end