#2591: Distribute Money to Maximum Children; solution & tests.

Author: vetalapo

c-sharp/Problems/math/DistributeMoneyToMaximumChildren.cs

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+/**
+ * 2591
+ * Distribute Money to Maximum Children
+ **
+ * You are given an integer money denoting the amount of money (in dollars)
+ * that you have and another integer children
+ * denoting the number of children that you must distribute the money to.
+ *
+ * You have to distribute the money according to the following rules:
+ *   • All money must be distributed.
+ *   • Everyone must receive at least 1 dollar.
+ *   • Nobody receives 4 dollars.
+ *
+ * Return the maximum number of children
+ * who may receive exactly 8 dollars
+ * if you distribute the money according to the aforementioned rules.
+ * If there is no way to distribute the money, return -1.
+ *
+ * Example 1:
+ *   Input: money = 20, children = 3
+ *   Output: 1
+ *   Explanation:
+ *     The maximum number of children with 8 dollars will be 1.
+ *     One of the ways to distribute the money is:
+ *       - 8 dollars to the first child.
+ *       - 9 dollars to the second child.
+ *       - 3 dollars to the third child.
+ *     It can be proven that no distribution exists
+ *     such that number of children getting 8 dollars is greater than 1.
+ *
+ * Example 2:
+ *   Input: money = 16, children = 2
+ *   Output: 2
+ *   Explanation: Each child can be given 8 dollars.
+ *
+ * Constraints:
+ *   • 1 <= money <= 200
+ *   • 2 <= children <= 30
+ *
+ * Hint 1:
+ *   Can we distribute the money according to the rules
+ *   if we give 'k' children exactly 8 dollars?
+ *
+ * Hint 2:
+ *   Brute force to find the largest possible value of k,
+ *   or return -1 if there doesn’t exist any such k.
+ **
+ * https://leetcode.com/problems/distribute-money-to-maximum-children/
+***/
+
+using System;
+
+namespace Problems;
+
+public class DistributeMoneyToMaximumChildren
+{
+    public int DistMoney( int money, int children )
+    {
+        money -= children;
+
+        if ( money < 0 )
+        {
+            return -1;
+        }
+
+        if ( children * 7 == money )
+        {
+            return children;
+        }
+
+        if ( money / 7 == children - 1 && money % 7 == 3 )
+        {
+            return children - 2;
+        }
+
+        return Math.Min( children - 1, money / 7 );
+    }
+}

c-sharp/Tests/math/DistributeMoneyToMaximumChildrenTests.cs

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+using NUnit.Framework;
+
+using Problems;
+
+public class DistributeMoneyToMaximumChildrenTests
+{
+    [TestCase( 20, 3, ExpectedResult = 1 )]
+    [TestCase( 16, 2, ExpectedResult = 2 )]
+    [TestCase( 1, 2, ExpectedResult = -1 )]
+    [TestCase( 12, 3, ExpectedResult = 1 )]
+    [TestCase( 9, 2, ExpectedResult = 1 )]
+    public int DistMoneyTest( int money, int children ) =>
+        new DistributeMoneyToMaximumChildren().DistMoney( money, children );
+}