N-th-Tribonacci_Number.java

class Solution {
    public int tribonacci(int n) {

        if(n <= 2){
            return (n == 0) ? 0 : 1;
        }

        int T_0 = 0, T_1 = 1, T_2 = 1, sum = 0;
        
        for(int i = 3; i <= n; i++){
            sum = T_0 + T_1 + T_2;
            T_0 = T_1; 
            T_1 = T_2; 
            T_2 = sum; 
        }

        return sum;
    }
}