class Solution {    public int tribonacci(int n) {                if(n ==0){            return 0;                    }                if (n ==1){            return 1;        }                if(n ==2){            return 1;        }                int [] dp = new int[n+1];                dp[0] =0;        dp[1] =1;        dp[2] =1;                for(int i =3; i<=n;i++){            dp[i]= dp[i-3]+dp[i-2]+dp[i-1];        }                return dp[n];            }}