深圳两个上机题，求讨论!

/**
 * 分析：
 * 0、设三个数分别为a、b、c；
 * 1、由于都是3位数，且b=2a，c=3a，所以a在100到400间
 * 2、9个数字不重复，故a最小值为123，最大329(333*3 < 1000)
 */

private void findD() {
  int min = 123;
  int max = 329;

  Pattern p = Pattern.compile("\\d*(\\d)\\d*\\1|0");
  
  for (int i = min; i < max; i++) {
     if(!p.matcher("" + i + 2*i + 3*i).find()) {
       System.out.println("a = " + i + ",b = " + 2*i + ",c = " + 3*i);
     }
  }
}

public static void main(String[] args) {
		int m = 0;
		int n = 0;
		String str = null;
		for(int i=123;i<345;i++){
			m = i*2;
			n = i*3;
			str = "" + i + m + n;
			byte[] b = str.getBytes();
			Arrays.sort(b);
			str = new String(b);
			if("123456789".equals(str)){
				System.out.println(i + ";" + m + ";" + n);
			}
		}
	}

192;384;576
219;438;657
273;546;819
327;654;981

这个看了会才明白，确实犀利

应该考得是递归全排列吧

package com.ll.test;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

public class T1 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		List<Integer> l = new ArrayList<Integer>();
		l.add(1);
		l.add(2);
		l.add(3);
		l.add(4);
		l.add(5);
		l.add(6);
		l.add(7);
		l.add(8);
		l.add(9);
		List<Integer> t = new ArrayList<Integer>();
		T1 a = new T1();
		a.fullPermutation(l, t);
	}

	public void fullPermutation(List<Integer> list, List<Integer> temp) {
		if (temp.size() == 9) {
			checkNumList(temp);
			return;
		}
		for (int i = 0; i < list.size(); i++) {
			List<Integer> newlist = new LinkedList<Integer>(list);
			List<Integer> newTemp = new LinkedList<Integer>(temp);
			newTemp.add(newlist.get(i));
			newlist.remove(i);
			fullPermutation(newlist, newTemp);
		}
	}

	public void checkNumList(List<Integer> temp) {
		int n1 = new Integer(temp.get(0) + "" + temp.get(1) + "" + temp.get(2));
		int n2 = new Integer(temp.get(3) + "" + temp.get(4) + "" + temp.get(5));
		int n3 = new Integer(temp.get(6) + "" + temp.get(7) + "" + temp.get(8));
		if (n1 == n3 * 3 && n2 == n3 * 2)
			System.out.println(n1 + " " + n2 + " " + n3);
	}
}

public static void main(String[] args) {
		int m = 0;
		int n = 0;
		String str = null;
		for(int i=123;i<345;i++){
			m = i*2;
			n = i*3;
			str = "" + i + m + n;
			byte[] b = str.getBytes();
			Arrays.sort(b);
			str = new String(b);
			if("123456789".equals(str)){
				System.out.println(i + ";" + m + ";" + n);
			}
		}
	}

192;384;576
219;438;657
273;546;819
327;654;981

public void method_1(){
		for (int i = 123; i <=333; i++) {
			String temp = i+""+(i*2)+""+(i*3);
			if(method_2(temp)){
				System.out.println(i+" "+(i*2)+" "+(i*3));
			}
		}
	}
	
	public boolean method_2(String str){
		try {
			Map<String, Integer> map = new HashMap<String, Integer>();
			for (int i = 0; i <= str.length(); i++) {
				if(map.containsKey(str.charAt(i)+"")){
					return false;
				}else{
					map.put(str.charAt(i)+"", i);
				}
			}
			return true;
		} catch (Exception e) {
			return true;
		}
	}

结果:

192  384  576
219  438  657
267  534  801
273  546  819
327  654  981
 

没有零，这组是错的

267  534  801