回形取数

题目描述

输入

输出

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
import java.util.Scanner;
public class Main1 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
while(in.hasNext()){
int n = in.nextInt();
int m = in.nextInt();
int[][] a=new int[n][m];
int[][] f=new int[n][m];//标志数组用来判断是否已经取过
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++){
a[i][j]=in.nextInt();
f[i][j]=0;
}
}
int cnt=1;
int x=0,y=0;
int[] b=new int[n*m];
b[0]=a[x][y];
f[x][y]=-1;
while(cnt<m*n){
while(x+1<n&&f[x+1][y]!=-1){b[cnt++]=a[++x][y];f[x][y]=-1;}
while(y+1<m&&f[x][y+1]!=-1){b[cnt++]=a[x][++y];f[x][y]=-1;}
while(x-1>=0&&f[x-1][y]!=-1){b[cnt++]=a[--x][y];f[x][y]=-1;}
while(y-1>=0&&f[x][y-1]!=-1){b[cnt++]=a[x][--y];f[x][y]=-1;}
}
for (int i = 0; i < b.length-1; i++)
System.out.print(b[i]+" ");
System.out.println(b[b.length-1] );//检查空格
}
}
}