Given an array {1, 2, 3, 1, 5, 6,} the output should be{1}
public void FirstRepeatingCahrecter(int[] arr){ int min=-1; HashSet hset = new HashSet(); for(int i=arr.Length-1;i>0;i—){ if(hset.Contains(arr[i])) min=i; else hset.add(arr[i]); } if(min!=-1){ Console.WriteLine(“The first repeating charecter is:”+ arr[min]); }else Console.WriteLine(“There is not repeating charecter in the array”);}
var duplicates = arr.GroupBy(x => x).Select(x => x.Count() > 1);return duplicates.First().key;
var duplicates = arr.GroupBy(x => x).Select(x => x.Count() > 1);
return duplicates.First().key;
string[] qwerty = { “Z”, “A”, “C”, “H”, “F”, “V”, “F”, “H”, “A” };
HashSet NoRepeat = new ();string? first_repeat = null;foreach (var item in qwerty){ if(!NoRepeat.Add(item)) { first_repeat = item; break; }}Console.WriteLine(first_repeat);
var duplicates = arr.GroupBy(x => x).Where(x => x.Count() });return duplicates.First().key;
var duplicates = arr.GroupBy(x => x).Select(x => new { key = x.Key, val = x.Count() }); return duplicates.First().key;