using System;
public static class DistanceFinder
{
/// <summary>
/// Finds the maximum distance between two values in an array.
/// Distance is defined as the absolute difference between indices.
/// </summary>
/// <param name="numbers">Input array.</param>
/// <param name="value1">First value to search for.</param>
/// <param name="value2">Second value to search for.</param>
/// <returns>
/// Maximum distance if both values exist; otherwise -1.
/// </returns>
public static int MaxDistanceBetweenValues(
int[] numbers,
int value1,
int value2)
{
int firstValue1 = -1;
int lastValue1 = -1;
int firstValue2 = -1;
int lastValue2 = -1;
// Find the first and last occurrence of both values.
for (int i = 0; i < numbers.Length; i++)
{
if (numbers[i] == value1) {
if (firstValue1 == -1) {
firstValue1 = i;
}
lastValue1 = i;
}
if (numbers[i] == value2) {
if (firstValue2 == -1) {
firstValue2 = i;
}
lastValue2 = i;
}
}
// One or both values were not found.
if (firstValue1 == -1 || firstValue2 == -1)
{
return -1;
}
// The maximum distance must involve extreme occurrences.
int distance1 = Math.Abs(firstValue1 - lastValue2);
int distance2 = Math.Abs(firstValue2 - lastValue1);
return Math.Max(distance1, distance2);
}
public static void Main()
{
int[] numbers =
{
2, 3, 7, 3, 3, 4, 8, 8, 8, 11, 9, 1, 3
};
int distance = MaxDistanceBetweenValues(numbers, 3, 8);
Console.WriteLine($"Maximum distance between 3 and 8: {distance}");
}
}
/*
run:
Maximum distance between 3 and 8: 7
*/
