Home >Java >javaTutorial >Solution to the problem of returning a sequence number array after sorting a two-dimensional array
MatrixElement class used by
package com.cdl.matrix; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; /** *@source:http://blog.csdn.net/justinavril/archive/2009/12/14/5003467.aspx * *@function: 矩阵A * * 68 36 22 * * 59 77 39 * * 81 20 17 * * 将矩阵A每列排序之后(升序排列)应该得到的矩阵是: * * 矩阵B: * * 59 20 17 * * 68 36 22 * * 81 77 39 * * 这样矩阵A中每个元素在矩阵B中对应的位置就是 * * 矩阵C: * * 2 3 3 * * 1 1 1 * * 3 2 2 * * 问:由矩阵A得到矩阵C的算法? * * @author ocaicai@yeah.net 2011-6-27 * */ public class MatrixColSort { /** * @param args */ public static void main(String[] args) { int[][] initArray = { { 68, 36, 22 }, { 59, 77, 39 }, { 81, 20, 17 } }; System.out.println("原来的数组:"); printArray(initArray); System.out.println("排序后的数组:"); MatrixElement[][] transferedArray = transferByElement(initArray); MatrixElement[][] sortedArray = sortArrayCols(transferedArray); int[][] targerArray = getRowsArray(sortedArray); printArray(targerArray); } /** * 将数组中单个的value转换成Element(value,rowIndex) * * @param sourceArray * @return */ public static MatrixElement[][] transferByElement(int[][] sourceArray) { int rows = sourceArray.length; int cols = sourceArray[0].length; MatrixElement[][] elementArray = new MatrixElement[rows][cols]; for (int row = 0; row < rows; row++) { for (int col = 0; col < cols; col++) { elementArray[row][col] = new MatrixElement( sourceArray[row][col], row + 1); } } return elementArray; } /** * 获取某一列的值存入一个临时的tempList中, * * 然后对这个tempList赋整列的值然后对其排序, * * 再把排序后的tempList赋值回列去 * * @param elementArray * 被转换的对象 * @return */ public static MatrixElement[][] sortArrayCols(MatrixElement[][] elementArray) { int rows = elementArray.length; int cols = elementArray[0].length; for (int colIndex = 0; colIndex < cols; colIndex++) { List<MatrixElement> tempList = new ArrayList<MatrixElement>(); for (int rowIndex = 0; rowIndex < rows; rowIndex++) { tempList.add(elementArray[rowIndex][colIndex]); } Collections.sort(tempList); for (int rowIndex = 0; rowIndex < rows; rowIndex++) { elementArray[rowIndex][colIndex] = tempList.get(rowIndex); } } return elementArray; } /** * @param elementArray * 从其中获取rowIndex,做成一个数组返回去 * @return */ public static int[][] getRowsArray(MatrixElement[][] elementArray) { int rows = elementArray.length; int cols = elementArray[0].length; int[][] rowArray = new int[rows][cols]; for (int row = 0; row < rows; row++) for (int col = 0; col < cols; col++) rowArray[row][col] = elementArray[row][col].getRowIndex(); return rowArray; } /** * 打印二维数组 * * @param array */ public static void printArray(int[][] array) { for (int i = 0; i < array.length; i++) System.out.println(Arrays.toString(array[i])); } }
:
package com.cdl.matrix; public class MatrixElement implements Comparable<MatrixElement> { int value; int rowIndex; public int getValue() { return value; } public void setValue(int value) { this.value = value; } public int getRowIndex() { return rowIndex; } public void setRowIndex(int rowIndex) { this.rowIndex = rowIndex; } public MatrixElement(int value, int rowIndex) { this.value = value; this.rowIndex = rowIndex; } @Override public int compareTo(MatrixElement anotherEmlement) { //比较只需要对value比较 int valueCmp = this.value - anotherEmlement.value; return valueCmp; } }
Output result:
原来的数组: [68, 36, 22] [59, 77, 39] [81, 20, 17] 排序后的数组: [2, 3, 3] [1, 1, 1] [3, 2, 2]