using System;
using System.Collections.Generic;
public class Program
{
static int GetMaxDistance(int[] arr) {
Dictionary<int, int> dict = new Dictionary<int, int>();
int maximumDistance = 0;
int size = arr.Length;
for (int i = 0; i < size; i++) {
if (!dict.ContainsKey(arr[i])) {
dict[arr[i]] = i;
Console.Write("dict[arr[i]]=" + dict[arr[i]]);
Console.Write(" arr[i]=" + arr[i]);
Console.WriteLine(" i=" + i);
}
else {
maximumDistance = Math.Max(maximumDistance, i - dict[arr[i]]);
Console.Write("dict[arr[i]]=" + dict[arr[i]]);
Console.Write(" i - dict[arr[i]]=" + (i - dict[arr[i]]));
Console.WriteLine(" i=" + i);
}
}
return maximumDistance;
}
public static void Main(string[] args)
{
int[] arr = new int[] {7, 1, 4, 3, 1, 5, 3, 4, 9, 1, 3};
Console.Write(GetMaxDistance(arr));
}
}
/*
run:
dict[arr[i]]=0 arr[i]=7 i=0
dict[arr[i]]=1 arr[i]=1 i=1
dict[arr[i]]=2 arr[i]=4 i=2
dict[arr[i]]=3 arr[i]=3 i=3
dict[arr[i]]=1 i - dict[arr[i]]=3 i=4
dict[arr[i]]=5 arr[i]=5 i=5
dict[arr[i]]=3 i - dict[arr[i]]=3 i=6
dict[arr[i]]=2 i - dict[arr[i]]=5 i=7
dict[arr[i]]=8 arr[i]=9 i=8
dict[arr[i]]=1 i - dict[arr[i]]=8 i=9
dict[arr[i]]=3 i - dict[arr[i]]=7 i=10
8
*/
