프로그래머스-2 x n 타일링

class Solution {
    public int solution(int n) {
     int answer = 0;
        int a = 1;
        int b = 2;
        
        if(n == 1)
        	answer = a;
        else if(n == 2)
        	answer = b;
        else {
        	for(int i=2; i<n; i++) {
        		if(i%2 == 0) {
        			a += b;
        			a = a%1000000007;
        		} else {
        			b += a;
        			b = b%1000000007;
        		}
        	}
        	
        	if(n%2 == 0)
        		answer = b;
        	else
        		answer = a;
        }
        
        return answer;
    }
}