package commonAlgorithm;public class PolynomialSoluter {  private double[][] matrix;  private double[] result;  private int order;  public PolynomialSoluter() {  }  // 檢查輸入項長度并生成增廣矩陣  private boolean init(double[][] matrixA, double[] arrayB) {    order = arrayB.length;    if (matrixA.length != order)      return false;    matrix = new double[order][order + 1];    for (int i = 0; i < order; i++) {      if (matrixA[i].length != order)        return false;      for (int j = 0; j < order; j++) {        matrix[i][j] = matrixA[i][j];      }      matrix[i][order] = arrayB[i];    }    result = new double[order];    return true;  }  public double[] getResult(double[][] matrixA, double[] arrayB) {    if (!init(matrixA, arrayB))      return null;    // 高斯消元-正向    for (int i = 0; i < order; i++) {      // 如果當前行對角線項為0則與后面的同列項非0的行交換      if (!swithIfZero(i))        return null;      // 消元      for (int j = i + 1; j < order; j++) {        if (matrix[j][i] == 0)          continue;        double factor = matrix[j][i] / matrix[i][i];        for (int l = i; l < order + 1; l++)          matrix[j][l] = matrix[j][l] - matrix[i][l] * factor;      }    }    // 高斯消元-反向-去掉了冗余計算    for (int i = order - 1; i >= 0; i--) {      result[i] = matrix[i][order] / matrix[i][i];      for (int j = i - 1; j > -1; j--)        matrix[j][order] = matrix[j][order] - result[i] * matrix[j][i];    }    return result;  }  private boolean swithIfZero(int i) {    if (matrix[i][i] == 0) {      int j = i + 1;      // 找到對應位置非0的列      while (j < order && matrix[j][i] == 0)        j++;      // 若對應位置全為0則無解      if (j == order)        return false;      else        switchRows(i, j);    }    return true;  }  private void switchRows(int i, int j) {    double[] tmp = matrix[i];    matrix[i] = matrix[j];    matrix[j] = tmp;  }}