package other;

public class interview_arrayshift {
    /**
     * n = 5
     * [1,2,3,4,5] or [5,4,3,2,1]
     * [1,2,3,4,5]: true : [0, +1, +1, +1, +1]
     * [3,4,5,1,2]: true : [0, +1, +1, -4, +1, +1]
     * *[4,5,1,2,3]: true : [0, +1, -4, +1, +1]
     * [5,1,2,3,4]: true : [0, -4, +1, +1, +1]
     * [5,4,1,2,3]: false
     * *[3,2,1,5,4]: true : [0, -1, -1, +4, -1]
     *
     */

    public static void main (String[] args) {


//        int[] ary = {1,2,3,4,5};
//        int[] ary = {4,5,1,2,3};
//        int[] ary = {4,5,6,7,8,1,2,3};
//        int[] ary = {7,8,4,5,6,1,2,3}; // wrong: double downs

//        int[] ary = {5,4,3,2,1};
//        int[] ary = {3,2,1,5,4};
//        int[] ary = {7,6,5,4,3,2,1,9,8};
        int[] ary = {3,2,1,7,6,5,9,8}; // wrong: double ups


        boolean result_asce = check_asec(ary);
        if (result_asce == true)
            System.out.println("result_asce: " + result_asce);

        boolean result_desc = check_desc(ary);
        if (result_desc == true)
            System.out.println("result_desc: " + result_desc);

    }

    private static boolean check_asec(int[] ary) {
        // O: ups
        // O: ups down ups
        // X: ups down down
        int correct_sum_1 = ary.length - 1;
        int correct_sum_2 = -1;

        int diff_sum;
        int sum = 0;
        int i_prev = 0;

        int count_go_down = 0;

        for (int i = 1; i < ary.length; i++) {
            int diff = ary[i] - ary[i_prev];
            if (diff < 0) count_go_down++;
            if (count_go_down > 1) return false;

            sum += diff;
            i_prev = i;
        }

        if (sum == correct_sum_1) {
            return true;
        }else if (sum == correct_sum_2) {
            return true;
        }

        return false;
    }


    private static boolean check_desc(int[] ary) {
        // O: downs
        // O: downs up downs
        // X: downs up downs
        int correct_sum_1 = -(ary.length - 1);
        int correct_sum_2 = +1;

        int diff_sum;
        int sum = 0;
        int i_prev = 0;

        int count_go_up = 0;

        for (int i = 1; i < ary.length; i++) {
            int diff = ary[i] - ary[i_prev];
            if (diff > 0) count_go_up++;
            if (count_go_up > 1) return false;

            sum += diff;
            i_prev = i;
        }

        if (sum == correct_sum_1) {
            return true;
        }else if (sum == correct_sum_2) {
            return true;
        }

        return false;
    }

}