算法-递归-中心对称数

namespace ZXDC;

public class ZXDCS{

    /// <summary>
    /// 前n位有多少中心对称数
    /// n=1 1 8 0
    /// n=2 11 69 96 88
    /// </summary>
    public static void Show()
    {
        var zt = ZXDCDFS(4,4);
        System.Console.WriteLine(string.Join("-",zt));
        foreach(var item in zt)
        {
            System.Console.WriteLine(string.Join("-",item));
        }
    }

    public static IList<string> ZXDCDFS(int n,int m){
        if(n <= 0) return new List<string>(){""};
        if(n == 1) return new List<string>(){"1","0","8"};

        var rtList = ZXDCDFS(n-2,m);
        if(m != n) rtList.Add("00");
        var rtNew = new List<string>();
        for(int i =0;i<rtList.Count;i++)
        {
            rtNew.Add("1"+ rtList[i] + "1");
            rtNew.Add("8"+ rtList[i] + "8");
            rtNew.Add("6"+ rtList[i] + "9");
            rtNew.Add("9"+ rtList[i] + "6");
        }
        return rtNew;
    }
}

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