N-th Tribonacci Number (Leetcode 1137)

Problem Link: https://leetcode.com/problems/n-th-tribonacci-number/

class Solution:
    def tribonacci(self, n: int) -> int:
        
        dp=[0 for i in range(n+1)]
        dp[0]=0
        if(n==0):
            return dp[n]
        dp[1]=1
        if(n==1):
            return dp[n]
        dp[2]=1
        if(n==2):
            return dp[n]
        for i in range(3,n+1):
            dp[i]=dp[i-1]+dp[i-2]+dp[i-3]
        return dp[n]