resistor-color-trio: fix

Author: ErikSchierboom

exercises/practice/resistor-color-trio/.meta/Example.cs

@@ -2,10 +2,22 @@
 
 public static class ResistorColorTrio
 {
-    private const int KiloOhms = 1_000;
-    private static readonly string[] AllColors = new[] { "black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white" };
-    public static string Label(string[] colors) => $"{(GetValue(colors) is int _value && _value >= KiloOhms ? _value / KiloOhms : _value)} " + GetUnit(_value);
-    private static int GetValue(string[] colors) => ((ResistorValue(colors[0]) * 10) + ResistorValue(colors[1])) * (int)Math.Pow(10, ResistorValue(colors[2]));
-    private static string GetUnit(int value) => (value >= KiloOhms ? "kilo" : "") + "ohms";
-    private static int ResistorValue(string color) => Array.IndexOf(AllColors, color);
+    private static readonly string[] Colors = ["black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white"];
+    private static readonly string[] Units = ["", "kilo", "mega", "giga"];
+    
+    public static string Label(string[] colors)
+    {
+        var ohms = Ohms(colors);
+
+        for (var i = 0; i < Units.Length; ++i)
+            if (ohms <= Math.Pow(1000, i + 1))
+                return $"{ohms / Math.Pow(1000, i)} {Units[i]}ohms";
+
+        throw new InvalidOperationException();
+    }
+
+    private static ulong Ohms(string[] colors) =>
+        (Value(colors[0]) * 10 + Value(colors[1])) * (ulong)Math.Pow(10, Value(colors[2])); 
+    
+    private static ulong Value(string color) => (ulong)Array.IndexOf(Colors, color);
 }