[Java] 蓝桥杯BASIC-25 基础练习回形取数

问题描述
回形取数就是沿矩阵的边取数，若当前方向上无数可取或已经取过，则左转90度。一开始位于矩阵左上角，方向向下。
输入格式
输入第一行是两个不超过200的正整数m, n，表示矩阵的行和列。接下来m行每行n个整数，表示这个矩阵。
输出格式
输出只有一行，共mn个数，为输入矩阵回形取数得到的结果。数之间用一个空格分隔，行末不要有多余的空格。
样例输入
3 3
1 2 3
4 5 6
7 8 9
样例输出
1 4 7 8 9 6 3 2 5
样例输入
3 2
1 2
3 4
5 6
样例输出
1 3 5 6 4 2

package base25;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int[][] a = new int[200][200];
        for (int k = 0; k < n; k++) {
            for (int k1 = 0; k1 < m; k1++) {
                a[k][k1] = in.nextInt();
            }
        }
        int all = n * m;
        int i = 0, j = 0;
        while (all > 0) {
            while (i < m && a[i][j] != -1) {//down
                System.out.print(a[i][j] + " ");
                a[i][j] = -1;
                i++;
                all--;
            }
            i--;
            j++;
            while (j < n && a[i][j] != -1) {//right
                System.out.print(a[i][j] + " ");
                a[i][j] = -1;
                j++;
                all--;
            }
            j--;
            i--;
            while (i >= 0 && a[i][j] != -1) {//up
                System.out.print(a[i][j] + " ");
                a[i][j] = -1;
                i--;
                all--;
            }
            i++;
            j--;
            while (j >= 0 && a[i][j] != -1) {//left
                System.out.print(a[i][j] + " ");
                a[i][j] = -1;
                j--;
                all--;
            }
            j++;
            i++;
        }

    }
}

package base25;

import java.util.Scanner;

public class Main {

public static void main(String[] args) {

Scanner in = new Scanner(System.in);

int n = in.nextInt();

int m = in.nextInt();

int[][] a = new int[200][200];

for (int k = 0; k < n; k++) {

for (int k1 = 0; k1 < m; k1++) {

a[k][k1] = in.nextInt();

}

int all = n * m;

int i = 0, j = 0;

while (all > 0) {

while (i < m && a[i][j] != -1) {//down

System.out.print(a[i][j] + " ");

a[i][j] = -1;

i++;

all--;

}

i--;

j++;

while (j < n && a[i][j] != -1) {//right

System.out.print(a[i][j] + " ");

a[i][j] = -1;

j++;

all--;

}

j--;

i--;

while (i >= 0 && a[i][j] != -1) {//up

System.out.print(a[i][j] + " ");

a[i][j] = -1;

i--;

all--;

}

i++;

j--;

while (j >= 0 && a[i][j] != -1) {//left

System.out.print(a[i][j] + " ");

a[i][j] = -1;

j--;

all--;

}

j++;

i++;

}

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