数字组合（未完成）

给定一组数字，求其中任意K个数的组合并将各种组合存储返回

来自一道1100分的topcoder习题，该死的递归快把人搞死了，从网上查到了解决方案但还是理解的不很透彻，最大问题是返回的String值不能对原数据进行区分，尝试用ArrayList也不行，现在脑子一团糟，在博客上记录一下，以后有更好的方法再过来改

如果路过的高手有什么好的建议，敬请指教

public class Polygons2 {
    static ArrayList co_term = new ArrayList();
    static int count = 0;
    public static void number(int[] segmention, int K) {
        long result = 0;
        int N = segmention.length;
        //cacu the number of ways of  combination
        int co_n = 1;
        for (int i = N; i > K; i--) {
            co_n *= i;
        }
        String temp = "";
        combin(segmention, K, temp, 0);
        String[] combin_result = (String[]) co_term.toArray(new String[co_term.size()]);
        //     combin_result=combin_result.substring(1,co_term.size()-1);
        for (String com : combin_result) {
            System.out.println(com);
        }
    }

    public static void combin(int[] original, int k, String temp, int start) {
        if (k == 0) {
            co_term.add(temp);
            //co_term.add(",");
        } else {
            for (int i = start; i < original.length; i++) {
                temp += (String.valueOf(original[i]));
                //co_term.add(" ");
                combin(original, k - 1, temp, i + 1);
                //co_term.remove(temp.substring(temp.length()));
                temp = temp.substring(0, temp.length() - 1);
            }
        }
    }
//    public static void combin(int[] original, int k, int start) {
//        ArrayList temp = new ArrayList();
//        if (k == 0) {
//            co_term.add(temp);
//            co_term.add(",");
//        } else {
//            for (int i = start; i < original.length; i++) {
//                temp.add(original[i]);
//                co_term.add(String.valueOf(original[i]) + " ");
//                combin(original, k - 1, temp, i + 1);
//                temp.remove(temp.size());
//            //co_term.remove(co_term.size()-1);
//            }
//        }
//    }
    public static void main(String[] args) {
        int[] segmention = {10, 1, 4, 9, 20};
        int K = 4;
        number(segmention, K);
    }
}