【Leetcode_easy】1137. N-th Tribonacci Number

class Solution {
public:
    int tribonacci(int n) {
        if(n==0) return 0;
        if(n==1 || n==2) return 1;
        int t0 = 0, t1 = 1, t2 = 1, t3 = 0;
        for(int i=3; i<=n; i++)
        {
            t3 = t0+t1+t2;
            t0 = t1;
            t1 = t2;
            t2 = t3;          
        }
        return t3;
    }
};