java习题-雷场布置

package task3_ZH3;

import java.util.Scanner;

public class Minefields {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		//输入部分
		Scanner in = new Scanner(System.in);
		System.out.println("请输入雷场的边场[5,20]之间：");
		int n = in.nextInt();
		System.out.println("请输入要布置的地雷数量（覆盖率不超过50%）：");
		int m = in.nextInt();
		
		//判断合法性
		while(n < 5 || n > 20 || m < 0 || m > n*n/2) {
			System.out.println("您输入的数据不符合要求。");
			System.out.println("请输入雷场的边场[5,20]之间：");
			n = in.nextInt();
			System.out.println("请输入要布置的地雷数量（覆盖率不超过50%）：");
			m = in.nextInt();
		}
		in.close();
		
		// 主体部分
		char[][] mineFields = new char[n][n];
	    int[] mines = new int[m];
	    mines[0] = (int)(Math.random() * n * n);
	    for (int i = 1; i < m; i++) {
	      int temp = (int)(Math.random() * n * n);
	      boolean isExist = false;
	      for (int j = 0; j < i; j++) {
	        if (temp == mines[j]) {
	          isExist = true;
	          break;
	        } 
	      } 
	      if (isExist) {
	        i--;
	      } else {
	        mines[i] = temp;
	      } 
	    } 
	    for (int i = 0; i < m; i++) {
	      int row = mines[i] / n;
	      int col = mines[i] % n;
	      mineFields[row][col] = '*';
	    } 
	    for (int i = 0; i < n; i++) {
	      for (int j = 0; j < n; j++) {
	        if (mineFields[i][j] != '*') {
	          int count = 0;
	          for (int tempI = i - 1; tempI <= i + 1; tempI++) {
	            for (int tempJ = j - 1; tempJ <= j + 1; tempJ++) {
	              if (tempI >= 0 && tempI < n && tempJ >= 0 && tempJ < n && 
	            		  mineFields[tempI][tempJ] == '*')
	                count++; 
	            } 
	          } 
	          mineFields[i][j] = (char)(48 + count);
	        } 
	      } 
	    } 
		// 打印部分
		System.out.println("生成的雷场如下：");
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				System.out.print(String.valueOf(mineFields[i][j])+" ");
			}
			System.out.println();
		}
	}

}