java 24点算法实现

折腾了一个中午写了一个24点的算法,试验了一下效果还不错,这个算法没有啥技巧也就是把全部的可能性给算一遍,代码如下:

/**
 * @author 百岁（[e-mail]）
 * @date 2013-3-27
 */
public class Test24 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// 需要计算的24点的四个值放置在一个数组中
		int[] param = new int[] { 2, 6, 5, 10 };

		for (int i = 0; i < param.length; i++) {
			for (int j = 0; j < param.length; j++) {
				if (i == j) {
					continue;
				}
				// System.out.println("i:" + param[i] + ",j:" + param[j]);

				for (Comput opr : computAry) {

					int degree2 = opr.comput(param[i], param[j]);

					for (int k = 0; k < param.length; k++) {

						Set<Integer> all = new HashSet<Integer>();
						all.add(i);
						all.add(j);
						all.add(k);
						if (all.size() < 3) {
							continue;
						}

						for (Comput opr2 : computAry) {
							int degree3 = opr2.comput(degree2, param[k]);
							for (int m = 0; m < param.length; m++) {

								all = new HashSet<Integer>();
								all.add(i);
								all.add(j);
								all.add(k);
								all.add(m);

								if (all.size() < 4) {
									continue;
								}

								for (Comput opr3 : computAry) {

									if (opr3.comput(degree3, param[m]) == 24) {
										// System.out.println("i:" + param[i]
										// + ",j:" + param[j] + ",k="
										// + param[k] + ",m=" + param[m]);

										System.out.println("" + param[i]
												+ opr.getSymbol() + param[j]
												+ opr2.getSymbol() + param[k]
												+ opr3.getSymbol() + param[m]);
									}
								}
							}
						}
					}
				}

			}
		}
	}

	static abstract class Comput {

		abstract int comput(int a, int b);

		abstract char getSymbol();
	}

	static class Plus extends Comput {

		@Override
		int comput(int a, int b) {
			return a + b;
		}

		@Override
		char getSymbol() {
			return '+';
		}
	}

	static class Subtraction extends Comput {

		@Override
		int comput(int a, int b) {
			return a - b;
		}

		@Override
		char getSymbol() {
			return '-';
		}
	}

	static class Times extends Comput {

		@Override
		int comput(int a, int b) {
			return a * b;
		}

		@Override
		char getSymbol() {
			return '*';
		}
	}

	static class Division extends Comput {
		@Override
		int comput(int a, int b) {
			return 0;
		}

		@Override
		char getSymbol() {
			return '/';
		}
	}

	final static Comput[] computAry = new Comput[] { new Plus(),
			new Subtraction(), new Times(), new Division() };

}