概要

using System.Linq;
using UnityEngine;

public class Example : MonoBehaviour
{
    private void Awake()
    {
        var list1 = new[] { 1, 2, 3 };
        var list2 = new[] { 1, 1, 1 };

        Debug.Log( list1.Distinct().Count() == 1 ); // False
        Debug.Log( list2.Distinct().Count() == 1 ); // True
    }
}