如何在Java中获得两个n维数组的总和？

在 Java中添加两个n维数组

addVectors

可以像这样添加Java中的两个1维数组/向量：

public static int[] addVectors( int[] a,int[] b )
{
    int[] c = new int[a.length];

    for ( int i = 0; i < a.length; i++ )
    {
        c[i] = a[i] + b[i];
    }

    return c;
}

addMatrices

可以像这样添加Java中的两个二维数组/矩阵：

public static int[][] addMatrices( int[][] a,int[][] b )
{
    int[][] c = new int[a.length][a[0].length];

    for ( int i = 0; i < a.length; i++ )
    {
        c[i] = addVectors( a[i],b[i] );
    }

    return c;
}

这两个函数都要求数组具有相同的大小以避免arrayOutOfBoundsException.

addArraysN

应该有一种方法可以使用递归添加两个未知维度的数组.
例如,以下代码使用假设函数addArraysN(arr1,arr2)

int[][][] a = { 
                { { 1,1,1 },{ 1,1 } },{ { 1,1 } }
              };
int[][][] b = { 
                { { 2,2,2 },{ 2,2 } },{ { 2,2 } }
              };
int[][][] sum = addArraysN( a,b );
System.out.println( java.util.Arrays.deepToString( sum ) );

应该输出

[[[3,3,3],[3,3]],[[3,3]]]

现在我想知道如何实现这个函数addArraysN(arr1,arr2).
我开始使用以下伪代码：

addArraysN( arr1,arr2 )
{
    int dimension = getDimension( arr1 );
    if ( dimension == 0 ) //there are no arrays,only numbers
        return arr1 + arr2;
    else
    {
        //create a new arrays with the same dimension and size as arr1 / arr2
        //loop through the fields with for
            //call itself when adding the fields of arr1 and arr2
        //return the sum
    }
}

可以使用java.lang.reflect.Array中的newInstance方法创建新数组.
循环可以像这样：

for ( int i = 0; i < ((int[])arr1).length; i++ )
    sum = addArraysN( ((int[])arr1)[i],((int[])arr2)[i] );

题

但我偶然发现了许多运行时错误和其他问题.有没有人知道如何实现这个addArrayN方法的想法甚至解决方案？

它也应该可以使用ArrayList或任何其他类,但我主要感兴趣的是如何使用数组…(但如果有人知道它请发布！)

提前致谢

附录1

我原来的代码：

import java.util.Arrays;
import java.lang.reflect.Array;

public class ArrayN
{
    public static void main( String[] args )
    {
        //Vector
        int[] vector1 = {0,4};
        int[] vector2 = {4,0};

        int[] vector3 = ArrayN.addVectors( vector1,vector2 );

        for ( int num : vector3 )
        {
            System.out.print( num );
        }
        System.out.println();

        System.out.println();

        //Matrix
        int[][] matrix1 = {{0,4},{4,0}};
        int[][] matrix2 = {{4,0},{0,4}};

        int[][] matrix3 = ArrayN.addMatrices( matrix1,matrix2 );

        for ( int[] vector : matrix3 )
        {
            for ( int num : vector )
            {
                System.out.print( num );
            }
            System.out.println();
        }

        System.out.println();

        //N-Array

        System.out.println( Arrays.deepToString( (Object[])ArrayN.addArraysN( (Object)matrix1,(Object)matrix2,5 ) ) );

    }

    public static int[] addVectors( int[] a,int[] b )
    {
        int[] c = new int[a.length];

        for ( int i = 0; i < a.length; i++ )
        {
            c[i] = a[i] + b[i];
        }

        return c;
    }

    public static int[][] addMatrices( int[][] a,int[][] b )
    {
        int[][] c = new int[a.length][a[0].length];

        for ( int i = 0; i < a.length; i++ )
        {
            c[i] = ArrayN.addVectors( a[i],b[i] );
        }

        return c;
    }

    public static Object addArraysN( Object arrayN1,Object arrayN2,int dimension,int innerlength )
    {
        if ( dimension == 0 )
        {
            return (int)arrayN1 + (int)arrayN2;
        }
        else
        {
            int[] dimensions = new int[dimension];
            for ( int i = 0; i < dimension; i++ )
            {
                dimensions[i] = innerlength;
            }
            Object arrayN3 = Array.newInstance( Array.class,dimensions );
            for ( int i = 0; i < Array.getLength( arrayN1 ); i++ )
            {
                Array.set( arrayN3,i,ArrayN.addArraysN( Array.get( arrayN1,i ),Array.get( arrayN2,dimension-1,innerlength ) );
            }

            return arrayN3;
        }
    }
}

输出：

44444

44444
44444

Exception in thread "main" java.lang.IllegalArgumentException: array element type mismatch
    at java.lang.reflect.Array.set(Native Method)
    at ArrayN.addArraysN(ArrayN.java:85)
    at ArrayN.addArraysN(ArrayN.java:85)
    at ArrayN.main(ArrayN.java:41)

附录2

我发现了错误.它是以下行：

Object arrayN3 = Array.newInstance( Array.class,dimensions );

我不得不用int.class替换Array.class.更正后的行应为：

Object arrayN3 = Array.newInstance( int.class,dimensions );

现在我意识到代码有另一个问题：
由于innerlength参数,多维数组中的每个数组必须具有相同的大小.如果数组较短,则其他值变为零：

44444

44444
44444

[[4,4,4],[4,[0,0],0]]

所以我首先使matrix1和matrix2更长一些：

//Matrix
int[][] matrix1 = {{0,4}};
int[][] matrix2 = {{4,0}};

但这不是一个好的解决方案.
Nikoloz写了一个方法来找出数组的维数.使用它和另一个方法arrayToString(Object)我现在编写了我的最终代码：

import java.util.Arrays;
import java.lang.reflect.Array;
import java.util.List;
import java.util.ArrayList;

public class ArrayN
{
    public static void main( String[] args )
    {
        int[][] matrix1 = {{0,4}};

        System.out.println( ArrayN.arrayToString( ArrayN.addArraysN( matrix1,matrix2 ) ) );

    }

    public static Object addArraysN( Object arrayN1,Object arrayN2 )
    {
        ArrayList<Integer> dimensions = new ArrayList<Integer>();
        ArrayN.getDimensions( arrayN1,dimensions );
        int[] dims = new int[dimensions.size()];
        for ( int i = 0; i < dims.length; i++ )
        {
            dims[i] = dimensions.get( i );
        }

        if ( dims.length == 0 )
        {
            return (int)arrayN1 + (int)arrayN2;
        }
        else
        {
            Object arrayN3 = Array.newInstance( int.class,dims );
            for ( int i = 0; i < Array.getLength( arrayN1 ); i++ )
            {
                Array.set( arrayN3,i ) ) );
            }

            return arrayN3;
        }
    }

    public static void getDimensions( Object array,List<Integer> dimensions )
    {
        if ( array != null && array.getClass().isArray() )
        {
            dimensions.add( Array.getLength( array ) );
            if ( Array.getLength( array ) > 0)
            {
                ArrayN.getDimensions( Array.get( array,0 ),dimensions );
            }
        }
    }

    public static String arrayToString( Object arr )
    {
        if ( arr instanceof byte[] )
            return Arrays.toString( (byte[])arr );
        else if ( arr instanceof short[] )
            return Arrays.toString( (short[])arr );
        else if ( arr instanceof int[] )
            return Arrays.toString( (int[])arr );
        else if ( arr instanceof long[] )
            return Arrays.toString( (long[])arr );
        else if ( arr instanceof float[] )
            return Arrays.toString( (float[])arr );
        else if ( arr instanceof double[] )
            return Arrays.toString( (double[])arr );
        else if ( arr instanceof char[] )
            return Arrays.toString( (char[])arr );
        else if ( arr instanceof boolean[] )
            return Arrays.toString( (boolean[])arr );
        else
            return Arrays.deepToString( (Object[])arr );
    }
}

另一种可能性是将维度1作为基本情况：

public static Object addArraysN( Object arrayN1,Object arrayN2 )
{
    ArrayList<Integer> dimensions = new ArrayList<Integer>();
    ArrayN.getDimensions( arrayN1,dimensions );
    int[] dims = new int[dimensions.size()];
    for ( int i = 0; i < dims.length; i++ )
    {
        dims[i] = dimensions.get( i );
    }
    if ( dims.length == 1 )
    {
        Object arrayN3 = Array.newInstance( int.class,dims );
        for ( int i = 0; i < Array.getLength( arrayN1 ); i++ )
        {
            int sum = ((int[])arrayN1)[i] + ((int[])arrayN2)[i];
            Array.set( arrayN3,sum );
        }
        return arrayN3;
    }
    else
    {
        Object arrayN3 = Array.newInstance( int.class,dims );
        for ( int i = 0; i < Array.getLength( arrayN1 ); i++ )
        {
            Array.set( arrayN3,(int[])ArrayN.addArraysN( Array.get( arrayN1,i ) ) );
        }

        return arrayN3;
    }
}

解决方法

这是完整而简单的解决方案.您可以将任何维数组传递给copyArray方法.

package com.azry.test;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;

public class MultiDimArray {

    public Object copyArray(Object srcArray1,Object srcArray2) {

        ArrayList<Integer> dimensions = new ArrayList<Integer>();
        getDimensions(srcArray1,dimensions);
        int[] dims = new int[dimensions.size()];
        for (int i = 0; i < dims.length; i++) {
            dims[i] = dimensions.get(i);
        }

        Object dstArray = Array.newInstance(int.class,dims);
        copyArray(srcArray1,srcArray2,dstArray);
        return dstArray;
    }

    public void copyArray(Object srcArray1,Object srcArray2,Object dstArray) {
        if (srcArray1 != null && srcArray1.getClass().isArray()) {
            if (srcArray1 instanceof int[]) {
                int[] s1 = (int[])srcArray1;
                int[] s2 = (int[])srcArray2;
                int[] d = (int[])dstArray;
                for (int i = 0; i < s1.length; i++) {
                    d[i] = s1[i] + s2[i];
                }
            }
            for (int i = 0; i < Array.getLength(srcArray1); i++) {
                copyArray(Array.get(srcArray1,i),Array.get(srcArray2,Array.get(dstArray,i));
            }
        }
    }

    public void getDimensions(Object array,List<Integer> dimensions) {
        if (array != null && array.getClass().isArray()) {
            dimensions.add(Array.getLength(array));
            if (Array.getLength(array) > 0) {
                getDimensions(Array.get(array,0),dimensions);
            }
        }
    }

    public static void main(String[] args) {

        int[][][] srcArray1 = new int[2][3][4];
        for (int i = 0; i < srcArray1.length; i++) {
            for (int j = 0; j < srcArray1[i].length; j++) {
                for (int k = 0; k < srcArray1[i][j].length; k++) {
                    srcArray1[i][j][k] = 2;
                }
            }
        }

        int[][][] srcArray2 = new int[2][3][4];
        for (int i = 0; i < srcArray2.length; i++) {
            for (int j = 0; j < srcArray2[i].length; j++) {
                for (int k = 0; k < srcArray2[i][j].length; k++) {
                    srcArray2[i][j][k] = 3;
                }
            }
        }

        int[][][] dstArray = (int[][][])new MultiDimArray().copyArray(srcArray1,srcArray2);

        for (int i = 0; i < dstArray.length; i++) {
            for (int j = 0; j < dstArray[i].length; j++) {
                for (int k = 0; k < dstArray[i][j].length; k++) {
                    System.out.println("[" + i + "," + j + "," + k + "] = " + dstArray[i][j][k]);
                }
            }
        }
    }
}

如何在Java中获得两个n维数组的总和？

解决方法

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