DouKaku?

using System;
using System.Text;
using System.Collections.Generic;
class Program {
    static void Main(string[] args) {
        StringBuilder ans = new StringBuilder();
        long ticks = System.DateTime.Now.Ticks;
        int count = 0;
        List<string> Q = new List<string>(new string[] { "1", "□", "2", "□", "3", "□", "4", "□", "5", "□", "6", "□", "7", "□", "8", "□", "9" });
        string[] MDPM = new string[] { "+", "-", "*", "/", " " };
        foreach(string a in MDPM) {
            foreach(string b in MDPM) {
                foreach(string c in MDPM) {
                    foreach(string d in MDPM) {
                        foreach(string e in MDPM) {
                            foreach(string f in MDPM) {
                                foreach(string g in MDPM) {
                                    foreach(string h in MDPM) {
                                        try {
                                            Q[1] = a; Q[3] = b; Q[5] = c; Q[7] = d; Q[9] = e; Q[11] = f; Q[13] = g; Q[15] = h;
                                        } catch(ArgumentOutOfRangeException) { }
                                        if(Eval(Q) == 100d) {
                                            foreach(string str in Q) {
                                                if(str != " ") {
                                                    ans.Append(str);
                                                }
                                            }
                                            ans.AppendLine();
                                            count++;
                                        }
                                    }
                                }

                            }

                        }

                    }

                }

            }

        }
        Console.Write(ans);
        Console.WriteLine(count);
        Console.WriteLine((System.DateTime.Now.Ticks - ticks) / 10000000L + "秒");
        Console.ReadLine();
    }

    static double Eval(List<string> formula) {
        List<string> fm = new List<string>(formula);
        while(fm.Contains(" ")) {
            int i = fm.IndexOf(" ");
            string tmp = fm[i - 1] + fm[i + 1];
            fm.RemoveAt(i - 1);
            fm.RemoveAt(i - 1);
            fm.RemoveAt(i - 1);
            fm.Insert(i - 1, tmp);
        }
        AnyCalc[] ac = new AnyCalc[] { Multi, Div };
        Calc("*", "/", "+", "-", fm, ac);
        ac = new AnyCalc[] { Plus, Minus };
        Calc("+", "-", "*", "/", fm, ac);

        return double.Parse(fm[0]);
    }

    static void Calc(string xc, string yc, string ac, string bc, List<string> fm, AnyCalc[] anyCalc) {
        while(fm.IndexOf(xc) != -1 || fm.IndexOf(yc) != -1) {
            List<string> x = new List<string>();
            List<string> y = new List<string>();
            string f = " ";
            int p = -1;
            for(int i = 0; i < fm.Count; i++) {
                double s;
                if(double.TryParse(fm[i], out s)) {
                    if(x.Count == 0) {
                        x.Add(fm[i]);
                    } else {
                        y.Add(fm[i]);
                    }
                } else if(fm[i] == xc || fm[i] == yc || fm[i] == ac || fm[i] == bc) {
                    p = i;
                    if(fm[i] == xc) {
                        f = xc;
                    } else if(fm[i] == yc) {
                        f = yc;
                    } else x.Clear();
                }
                if(y.Count >= 1) {
                    string tmp;
                    tmp = anyCalc[f == xc ? 0 : 1](fm[p - 1], fm[p + 1]);
                    for(int j = 1; j <= 3; j++) { fm.RemoveAt(p - 1); }
                    fm.Insert(p - 1, tmp);
                    break;
                }
            }
        }
    }

    delegate string AnyCalc(string x, string y);

    static string Plus(string x, string y) {
        return (double.Parse(x) + double.Parse(y)).ToString();
    }
    static string Minus(string x, string y) {
        return (double.Parse(x) - double.Parse(y)).ToString();
    }
    static string Multi(string x, string y) {
        return (double.Parse(x) * double.Parse(y)).ToString();
    }
    static string Div(string x, string y) {
        return (double.Parse(x) / double.Parse(y)).ToString();
    }
}