java - 矩阵交换行 - Java

Question

我需要编写一段代码来加载方阵，然后将第一行与第一列中元素最大的行交换，然后打印交换的数组。

我可以获得第一列的最大元素，但我不知道如何进行交换。

import java.io.*;
import java.util.*;
import static java.lang.System.out;

class Matriz4_Metodos{

    static String cadena;
    static InputStreamReader entrada = new InputStreamReader(System.in);
    static BufferedReader recibedatos = new BufferedReader(entrada);

    public static void main (String[] args) throws java.io.IOException {
    int n,mayor=0;

    n=LeerNumero("Ingresa el numero de los renglones y columnas:");

    int Matriz[][] = new int [n][n];

    Matriz=CargarMatriz(Matriz);

    ImprimirMatriz(Matriz);

    out.println("\nEl mayor de la primera columna es:"+EncontrarMayor(Matriz,mayor));

    }

    public static int LeerNumero (String msgtxt) throws java.io.IOException{

        do{
        int xnm;
        out.print(msgtxt);
        cadena=recibedatos.readLine();
        try{
        xnm=Integer.parseInt(cadena);
            if (xnm<0){
             out.println("Solo positivos");
             continue;
            }
            return xnm;
        }   
            catch (NumberFormatException e){
                out.println("Numero de dato incorrecto");
            }
        }while(true);

    }

    public static int[][] CargarMatriz (int xMatriz[][]) throws java.io.IOException{
    Random Aleatorio =new Random();
    int nal;
        for(int i=0; i<xMatriz.length; i++){
            for(int j=0; j<xMatriz[0].length; j++){
                nal=Aleatorio.nextInt(10);
                xMatriz[i][j]=nal;
            }

        }

        return xMatriz;
    }

    public static void ImprimirMatriz (int xMatriz[][]){
        out.println("\n");
        for(int i=0; i<xMatriz.length; i++){
            for(int j=0; j<xMatriz[0].length; j++){
                out.print(xMatriz[i][j]+" ");
            }
            out.println("\n");
        }
    }

    public static int EncontrarMayor (int xMatriz[][],int xmayor) throws java.io.IOException {
        xmayor=0;

        for(int i=0; i<xMatriz.length; i++){
            for(int j=0; j<xMatriz[0].length; j++){
                if(j==0){
                    if(xMatriz[i][j]>xmayor){
                    xmayor=xMatriz[i][j];
                    }
                }
            }
        }
        return xmayor;
    }

}

Answer 1

在上一个问题 Matrix Swapping Columns - Java 中找到答案交换列。

这是代码。 如需更多说明，请阅读内嵌评论。

    int[][] arr = new int[][] { { 1, 4, 5, 4 }, { 7, 6, 4, 2 }, { 1, 1, 2, 3 }, { 1, 2, 2, 5 } };

    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr[i].length; j++) {
            System.out.print(arr[i][j] + "\t");
        }
        System.out.println();
    }

    // logic begins here
    int rowWithHighestValueInFirstColumn = 1;
    for (int i = 0; i < arr[rowWithHighestValueInFirstColumn].length; i++) {
        // store the value of highest row
        int temp = arr[rowWithHighestValueInFirstColumn][i];
        // swap the value of highest row with first row
        arr[rowWithHighestValueInFirstColumn][i] = arr[0][i];
        // set the value of first row that is stored in temp
        arr[0][i] = temp;
    }
    // logic ends here

    System.out.println("After swapping");
    for (int i = 0; i < arr.length; i++) {
        for (int j = 0; j < arr[i].length; j++) {
            System.out.print(arr[i][j] + "\t");
        }
        System.out.println();
    }

输出:(第二行与第一行交换)

    1   4   5   4   
    7   6   4   2   
    1   1   2   3   
    1   2   2   5   
    After swapping
    7   6   4   2   
    1   4   5   4   
    1   1   2   3   
    1   2   2   5