NTHU Online Judge #10236

/**
 * Name: NTHU Online Judge #10236 - Lab06
 * @author LinChuWen
 * Date: 2014.11.16
 * NCHU EE, Taichung, Taiwan
 *
 * Problem: http://acm.cs.nthu.edu.tw/problem.php?pid=10236
 * Description: Given a number N, we can create an N by N matrix as below:
 *           1   2   3   4   5
 *          16  17  18  19   6
 *          15  24  25  20   7
 *          14  23  22  21   8
 *          13  12  11  10   9
 *      In this case, N = 5, and the elements are in order from 1 to N^2 as a clockwise spiral pattern.
 *      Note that we always start from the upper left corner.
 */
import java.util.Scanner;

public class NTHU_10236_Lab06 {
    private static Scanner input = new Scanner(System.in);
    private static int width;

    public static void main(String[] args){
        System.out.println("Creating an N by N matrix......");
        System.out.print("Please input an integer N: ");
        while(input.hasNext()){
            width = input.nextInt();
            int[][] Matrix = new int[width][width];

            if(width%2==0)
                printMatrix(flipMatrix(buildMatrix(Matrix)));
            else printMatrix(buildMatrix(Matrix));
        } //while end
    } //main end

    private static int[][] buildMatrix( int[][] buildMatrixInput){
        int fillTimes=width;
        int cntFillColumn=0,cntFillRow=0;
        int indexRow=0,indexColumn=0;
        int startRow=0,startColumn=0;
        int cntFlipTimes=0;
        boolean goFlip=false;

        for(int countUp=1;countUp<=width*width;countUp++){

            if(goFlip){
                buildMatrixInput=flipMatrix(buildMatrixInput);
                cntFlipTimes++;
                fillTimes--;
                goFlip=false;

                if(cntFlipTimes%2==0)
                    startRow++;
                else startColumn++;

                indexRow=startRow;
                indexColumn=startColumn;
                cntFillColumn=0;cntFillRow=0;
            } //if(goFlip) end

            //fill content into Matrix
            if(cntFillColumn<fillTimes){
                buildMatrixInput[indexRow][indexColumn]=countUp;
                indexColumn++;cntFillColumn++;
            }else{
                indexRow++;cntFillRow++;
                buildMatrixInput[indexRow][indexColumn-1]=countUp;

                if(cntFillRow==fillTimes-1)
                    goFlip=true;
            } //fill Matrix end

        } //big for end

        return buildMatrixInput;
    } //buildMatrix() end

    private static int[][] flipMatrix( int[][] flipMatrixInput ){
        int[][] arrayFlip = new int[width][width];
        int cntDown_r,cntDown_c;
        cntDown_r=width-1;
        for(int cntUp_r=0;cntUp_r<width;cntUp_r++){
            cntDown_c=width-1;
            for(int cntUp_c=0;cntUp_c<width;cntUp_c++){
                arrayFlip[cntDown_r][cntDown_c] = flipMatrixInput[cntUp_r][cntUp_c];
                cntDown_c--;
            } //small for end
            cntDown_r--;
        } //big for end
        return arrayFlip;
    } //flipMatrix() end

    private static void printMatrix( int[][] printMatrixInput){
        int cnt1,cnt2;
        for(cnt1=0;cnt1<width;cnt1++){
            for(cnt2=0;cnt2<width;cnt2++){
                System.out.printf("%3d ", printMatrixInput[cnt1][cnt2]);
            } //small for end
            System.out.printf("\n");
        } //big for end
    } //printMatrix() end

} //class end