1700. Number of students unable to eat lunch

//1700. Number of students unable to eat lunch

class Solution {
    public int countStudents(int[] students, int[] sandwiches) {
        int zero_cnt = 0, one_cnt = 0;

        for(int i = 0; i < students.length; i++) {
            if(students[i] == 0) {
                zero_cnt++;
            }
            
            else{
                one_cnt++;
            }
        }

        for(int i = 0; i < sandwiches.length; i++) {
            if(sandwiches[i] == 0 && zero_cnt == 0) {
                return one_cnt;
            }

            if(sandwiches[i] == 1 && one_cnt == 0) {
                return zero_cnt;
            }

            if(sandwiches[i] == 0) {
                zero_cnt--;
            }
            
            else{
                one_cnt--;
            }
        }
        
        return 0;
    }
}