package demo;
public class MatrixInverse {
  public static double Det(double [][]Matrix,int N)//計算n階行列式（N=n-1）
  {
    int T0;
    int T1;
    int T2;
    double Num;
    int Cha;
    double [][] B;
    if(N>0)
    {
      Cha=0;
      B=new double[N][N];
      Num=0;
      if(N==1)
      {
        return Matrix[0][0]*Matrix[1][1]-Matrix[0][1]*Matrix[1][0];
      }
      for (T0=0;T0<=N;T0++)//T0循環
      {
        for (T1=1;T1<=N;T1++)//T1循環
        {
          for (T2=0;T2<=N-1;T2++)//T2循環
          {
            if(T2==T0)
            {
              Cha=1;
            }
            B[T1-1][T2]=Matrix[T1][T2+Cha];
          }
          //T2循環
          Cha=0;
        }
        //T1循環
        Num=Num+Matrix[0][T0]*Det(B,N-1)*Math.pow((-1),T0);
      }
      //T0循環
      return Num;
    } else if(N==0)
        {
      return Matrix[0][0];
    }
    return 0;
  }
  public static double Inverse(double[][]Matrix,int N,double[][]MatrixC){
    int T0;
    int T1;
    int T2;
    int T3;
    double [][]B;
    double Num=0;
    int Chay=0;
    int Chax=0;
    B=new double[N][N];
    double add;
    add=1/Det(Matrix,N);
    for ( T0=0;T0<=N;T0++)
    {
      for (T3=0;T3<=N;T3++)
      {
        for (T1=0;T1<=N-1;T1++)
        {
          if(T1<T0)
          {
            Chax=0;
          } else
          {
            Chax=1;
          }
          for (T2=0;T2<=N-1;T2++)
          {
            if(T2<T3)
            {
              Chay=0;
            } else
            {
              Chay=1;
            }
            B[T1][T2]=Matrix[T1+Chax][T2+Chay];
          }
          //T2循環
        }//T1循環
        Det(B,N-1);
        MatrixC[T3][T0]=Det(B,N-1)*add*(Math.pow(-1, T0+T3));
      }
    }
    return 0;
  }
  public static void main(String[]args)//測試
  {
    double[][] TestMatrix = {
           {1, 22, 34,22},
           {1, 11,5,21} ,
           {0,1,5,11},
           {7,2,13,19}};
    double[][]InMatrix=new double[4][4];
    Inverse(TestMatrix,3,InMatrix);
    String str=new String("");
    for (int i=0;i<4;i++)
    {
      for (int j=0;j<4;j++)
      {
        String strr=String.valueOf(InMatrix[i][j]);
        str+=strr;
        str+=" ";
      }
      str+="\n";
    }
    System.out.println("億速云測試結果：");
    System.out.println(str);
  }
}