ITSA 39

ITSA 39.cs

//ITSA 39 - Problem_1重點函數
static int[] Problem_1(int Start) {
    List<int> result = new List<int>();
    do {
        result.Add(Start);
        if(Start % 2 == 0) Start /= 2;
        else Start = Start * 3 + 1;
    } while(Start != 1);
    result.Add(1);
    return result.ToArray();
}
//=====

//ITSA 39 - Problem_2重點函數
static int[,] Problem_2(int[,] A,int[,] B) {
    for(int i = 0; i < A.GetLength(0); i++) {
        for(int j = 0; j < A.GetLength(1); j++) {
            A[i ,j] *= B[i ,j];
        }
    }
    return A;
}
//=====

//ITSA 39 - Problem_3重點函數
static int Problem_3(int Level,int[] M) {//M預設為1,2，LEVEL表示階梯數量，M表示可以跨出步數
    if(Level < 0)return 0;
    if(Level == 0)return 1;
    int result = 0;
    foreach(int value in M) {
        result+=Problem_3(Level - value ,M);
    }
    return result;
}
//=====

//ITSA 39 - Problem_4重點函數
static string Problem_4(string Input) {
    if(Input.Length == 0)return string.Empty;            
    switch(Input[0]) {
        case 'a':
            return Input[0] + Problem_4(new string(Input.Substring(1).Reverse().ToArray()));
        case 'b':
            return Input[0] + Problem_4(Input.Substring(1) + Input.Substring(1));
        case 'c':
            return Input[0] + Problem_4(Input.Substring(1).Remove(0 ,2));
        default:
            return Input[0] + Problem_4(Input.Substring(1));
    }
}
//=====

//ITSA 39 - Problem_5重點函數
static List<List<int>> Problem_5(int Max,List<int> MemberCount,List<int> Old = null) {//湊隊伍人數至MAX且多餘人數最少
    MemberCount = (from t in MemberCount where t != Max select t).ToList<int>();
    if(Old == null)Old = new List<int>();
    if(Old.Sum() >= Max)return new List<List<int>>(new List<int>[]{Old});
    List<List<int>> result = new List<List<int>>();
    foreach(int MCount in MemberCount) {
        List<int> Item = new List<int>(Old);//Copy
        List<int> CopyMember = new List<int>(MemberCount);
        Item.Add(MCount);CopyMember.Remove(MCount);

        result.AddRange(Problem_5(Max ,CopyMember ,Item));
    }
    result.Sort((A,B) => {
        Stack<int> As = new Stack<int>(A);
        Stack<int> Bs = new Stack<int>(B);
        int ASum = 0,index = 0, BSum = 0;
        while(As.Count > 0)ASum += As.Pop() * (int)Math.Pow(10 ,index++);
        index = 0;
        while(Bs.Count > 0)BSum += Bs.Pop() * (int)Math.Pow(10 ,index++);
        return ASum - BSum;
    });

    return (from t in result orderby t.Sum() select t).ToList<List<int>>();
}