diff --git a/DataStructures/Matrix/MatrixFastPower.java b/DataStructures/Matrix/MatrixFastPower.java index c2bdcf7cb..19f8528a3 100644 --- a/DataStructures/Matrix/MatrixFastPower.java +++ b/DataStructures/Matrix/MatrixFastPower.java @@ -1,5 +1,3 @@ -import java.util.*; - /** * * Java implementation of Matrix fast power @@ -14,11 +12,67 @@ import java.util.*; * other Matrix basic operator is based on @author Kyler Smith, 2017 * * @author DDullahan, 2018 - * + * */ +class MatrixFastPower { + + /** + * Matrix Fast Power + * + * @param matrix : square Matrix + * @param k : power of Matrix + * @return product + */ + public static Matrix FastPower(Matrix matrix, int k) throws RuntimeException { + + if(matrix.getColumns() != matrix.getRows()) + throw new RuntimeException("Matrix is not square Matrix."); + + int[][] newData = new int[matrix.getColumns()][matrix.getRows()]; + + for(int i = 0; i < matrix.getColumns(); i++) + newData[i][i] = 1; + + Matrix newMatrix = new Matrix(newData), + coMatrix = new Matrix(matrix.data); + + while(k != 0) { + + if((k & 1) != 0) + newMatrix = newMatrix.multiply(coMatrix); + + k >>= 1; + coMatrix = coMatrix.multiply(coMatrix); + + } + + return newMatrix; + } + + public static void main(String[] argv) { + + int[][] data = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}; + Matrix matrix = new Matrix(data); + + System.out.println("original matrix : "); + System.out.println(matrix.toString()); + + matrix = MatrixFastPower.FastPower(matrix, 5); + + System.out.println("after power : "); + System.out.println(matrix.toString()); + + matrix = MatrixFastPower.FastPower(matrix, 1000000); + + System.out.println("notice, large power may cause overflow : "); + System.out.print(matrix.toString()); + System.out.println("you can use mod to fix that :-) "); + + } +} class Matrix { - private int[][] data; + public int[][] data; /** * Constructor for the matrix takes in a 2D array @@ -106,34 +160,32 @@ class Matrix { } /** - * Matrix Fast Power - * - * @param k : power of Matrix - * @return product - */ - public Matrix MatrixFastPower(int k) throws RuntimeException { + * Returns the Matrix as a String in the following format + * + * [ a b c ] ... + * [ x y z ] ... + * [ i j k ] ... + * ... + * + * @return Matrix as String + * TODO: Work formatting for different digit sizes + */ + public String toString() { + String str = ""; - if(this.getColumns() != this.getRows()) - throw new RuntimeException("Matrix is not square Matrix."); + for(int i = 0; i < this.data.length; i++) { + str += "[ "; - int[][] newData = new int[this.getColumns()][this.getRows()]; - - for(int i = 0; i < this.getColumns(); i++) - newData[i][i] = 1; - - Matrix newMatrix = new Matrix(newData), - coMatrix = new Matrix(this.data); - - while(k != 0) { - - if((k & 1) != 0) - newMatrix = newMatrix.multiply(coMatrix); - - k >>= 1; - coMatrix = coMatrix.multiply(coMatrix); + for(int j = 0; j < this.data[0].length; j++) { + str += data[i][j]; + str += " "; + } + str += "]"; + str += "\n"; } - return newMatrix; + return str; } + }