class Solution {
public int tribonacci(int n) {
if (n == 0)
return 0;
else if (n == 1)
return 1;
else if (n == 2)
return 1;
int t0 = 0;
int t1 = 1;
int t2 = 1;
for (int i = 3; i <= n; i++) {
int tmpT1 = t1;
int tmpT2 = t2;
t2 = t0 + t1 + t2;
t1 = tmpT2;
t0 = tmpT1;
}
return t2;
}
}