[프로그래머스] 종이자르기 java

class Solution {
    public int solution(int M, int N) {
 	        int answer = 0;
	        if (M<0  || N<0) return 0;
	        answer+=M-1;
	        answer+=M*(N-1);
	        return answer;
    }
}

 

다른사람풀이 

class Solution {
    public int solution(int M, int N) {
        return M - 1 + (N - 1 ) * M;
    }
}