DSA-Java-Leetcode/1137. N-th Tribonacci Number at main · risitadas/DSA-Java-Leetcode · GitHub

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class Solution {
    public int tribonacci(int n)
    {


    int[] dp = {0, 1, 1};

        for (int i = 3; i <= n; ++i)
        {

            dp[i % 3] = dp[0] + dp[1] + dp[2];


        }

        return dp[n % 3];


/*

    if (n < 2)
      return n;

    int[] dp = {0, 1, 1};

    for (int i = 3; i <= n; ++i) {
      final int next = dp[0] + dp[1] + dp[2];
      dp[0] = dp[1];
      dp[1] = dp[2];
      dp[2] = next;
    }

    return dp[2];


*/


/*
        if(n==0)
        {
            return 0;

        }

        if(n==1)
        {
            return 1;

        }

        if(n==2)
        {
            return 1;

        }

        int x = 0, y = 1, z = 1, a = 0;

        for(int i=3; i<=n; i++)
        {

            a = x + y + z;
            x = y;
            y = z; z = a;


        }

        return a;
*/


    }
}