Day 4 of 100 Days LeetCode Challenge

LeetCode Challenge #1137. N-th Tribonacci Number

The Tribonacci sequence Tn is defined as follows: 

T0 = 0, T1 = 1, T2 = 1, and Tn+3 = Tn + Tn+1 + Tn+2 for n >= 0.

Given n, return the value of Tn.

 

Example 1:

Input: n = 4
Output: 4
Explanation:
T_3 = 0 + 1 + 1 = 2
T_4 = 1 + 1 + 2 = 4

Example 2:

Input: n = 25
Output: 1389537

 

Constraints:

  • 0 <= n <= 37
  • The answer is guaranteed to fit within a 32-bit integer, ie. answer <= 2^31 - 1.
Video Solution
Java Solution
				
					class Solution {
    public int tribonacci(int n) {
        if( n==0){
            return 0;
        }else if ( n==1 || n==2){
            return 1 ;
        }

        int ft = 0 ;
        int st = 1 ;
        int tt = 1 ;

        for(int i=1 ; i<=n;i++){
            int fot = ft + st + tt ;
            ft = st ;
            st = tt ;
            tt = fot ;
        }

        return ft ;
    }
}
				
			
Flowchart of Java Solution
Flowchart of LeetCode Problem 1137 Tribonacci Number e1697828480805

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