一段找零算法的特殊案例，指定找零的钱币数量

import java.util.Stack;

class Money {
  int fen;

  int number;
}

/**
 * 查找所有的找零算法，并显示数量符合规定的结果
 * 
 * @author 赵学庆 www.java2000.net
 */
public class T {
  static Stack<Money> stack = new Stack<Money>();

  // 假设只有10元、5元、2元和1元。如果更多，请自行添加，记得金额从大到小排列
  static int[] nums = new int[] { 10, 5, 2, 1 };

  public static void fen(int target, int sum, int index, int specialItem) {
    for (int i = index; i < nums.length; i++) {
      int num = nums[i];
      if (num > target) { // 如果面值超过找零的数值，则忽略
        continue;
      }
      Money m = new Money();
      m.fen = num;
      stack.push(m);
      while (sum + num <= target) {
        m.number++;
        if (sum + num == target) {
          showResult(specialItem);
        }
        sum += num;
        fen(target, sum, i + 1, specialItem);
      }
      stack.pop();
      sum -= m.fen * m.number;
    }
  }

  private static void showResult(int specialItem) {
    StringBuilder b = new StringBuilder();
    for (Money m : stack) {
      if (m.number > 0) {
        b.append(m.fen + ":" + m.number + " ");
        specialItem -= m.number;
      }
    }
    if (specialItem == 0) {
      System.out.println(b.toString());
    }
  }

  public static void main(String[] input) throws Exception {
    fen(190, 0, 0, 20); // 测试找190元，同时必须是20张
  }
}