2015a_91que2

    public static boolean what(int[] a, int num)
    {
        int start = 0;
        int sum = a[0];
        int end = 1;
        while(start < a.length){
            if(sum == num)
                return true;
            else if(sum > num){
                sum -= a[start];
                start++;
            }
            else if(end < a.length){
                sum += a[end];
                end++;
            }
            else
                return false;
        }
        return sum == num;
    }