Java-按行總和對2D數組排序

Question

嘗試編寫一種以增加行總和的順序交換2D數組的行的方法。

例如，如果我有以下2d數組：

int [][] array = {4,5,6},{3,4,5},{2,3,4};

我希望它這樣輸出一個數組：

{2 3 4}, {3 4 5}, {4 5 6}

方法：

a。）取每一行的總和，並制成總和的一維數組

b。）對rowSum數組進行冒泡排序

c。）根據進行的冒泡排序交換來交換原始數組的行

d。）然后打印新行排序的數組。

到目前為止，這是我的代碼：

      public void sortedArrayByRowTot() {
        int [][] tempArray2 = new int [salaryArray.length [salaryArray[0].length];

        for (int i = 0; i < tempArray2.length; i++) {
          for (int j = 0; j < tempArray2[i].length; j++) {
            tempArray2[i][j] = salaryArray[i][j];
          }
        }

        int [] rowSums = new int [tempArray2.length];
        int sum = 0;
        for (int i = 0; i < tempArray2.length; i++) {
          for (int j = 0; j < tempArray2[i].length; j++) {
            sum += tempArray2[i][j];
          }
          rowSums[i] = sum;
          sum = 0;
        }

        int temp;
        int i = -1;
        for(int j = rowSums.length; j > 0; j--){
          boolean isSwap = false;
          for (i = 1; i < j; i++) {
            if(rowSums[i-1] > rowSums[i]) {
              temp = rowSums[i-1];
              rowSums[i-1] = rowSums[i];
              rowSums[i] = temp;
              isSwap = true;
            }
          }

          if(!isSwap){
            break;
          }
        }

        for (int k = 0; k < tempArray2.length; k++) {
          temp = tempArray2[i-1][k];
          tempArray2[i-1][k] = tempArray2[i][k];
          tempArray2[i][k] = temp;
        }

        for (int b = 0; b < tempArray2.length; b++) {
          for (int c = 0; c < tempArray2[b].length; c++) {
            System.out.print(tempArray2[b][c] + " ");
          }
        }
      }
    }

不確定我是否正確執行了方法的c部分？

它一直說“線程“ main”中的異常 java.lang.ArrayIndexOutOfBoundsException：2”

Answer 1

正如@shmosel所說，您可以這樣操作：

public static void sortedArrayByRowTot() {
    int [][] array = {{4,5,6},{3,4,5},{2,3,4}};
    Arrays.sort(array, Comparator.comparingInt(a -> IntStream.of(a).sum()));
}

Answer 2

我能夠解決我的問題。 謝謝。

    public void sortedArrayByRowTot() {
      //Creates tempArray2 to copy salaryArray into
      int [][] tempArray2 = new int [salaryArray.length][salaryArray[0].length];

      //Copies salaryArray into tempArray2
      for (int i = 0; i < salaryArray.length; i++) {
        for (int j = 0; j < salaryArray[i].length; j++) {
          tempArray2[i][j] = salaryArray[i][j];
        }
      }

      //Creates rowSum array to store sum of each row
      int [] rowSums = new int [tempArray2.length];
      for (int i = 0; i < tempArray2.length; i++) {
        for (int j = 0; j < tempArray2[0].length; j++) {
          rowSums[i] += tempArray2[i][j];
        }
      }

      //Modified Bubble Sort of rowSum array (highest to lowest values)
      int temp;
      int i = 0;
      for(int j = rowSums.length; j > 0; j--){
        boolean isSwap = false;
        for (i = 1; i < j; i++) {
          if(rowSums[i-1] < rowSums[i]) {
            temp = rowSums[i-1];
            rowSums[i-1] = rowSums[i];
            rowSums[i] = temp;
            isSwap = true;
            //swaps rows in corresponding tempArray2 
            int [] temp2 = tempArray2[i-1];
            tempArray2[i-1] = tempArray2[i];
            tempArray2[i] = temp2;
          }
        }

        if(!isSwap){
          break;
        }
      }  

      //Prints sorted array 
      System.out.println("Sorted array: ");
      for (i = 0; i < tempArray2.length; i++) {
        for (int j = 0; j < tempArray2[i].length; j++) {
          System.out.print("$"+ tempArray2[i][j] + " ");
        }
        System.out.println();
      }
    } 

Answer 3

您可以嘗試這種方式。 我已經解決了。

 public class Solution{
          public static void sortedArrayByRowTot() {
            int [][] salaryArray = { {4,5,6},{3,4,5},{2,3,4} };
            int [][] tempArray2 = new int [salaryArray.length][salaryArray[0].length];

            for (int i = 0; i < salaryArray.length; i++) {
              for (int j = 0; j < salaryArray[i].length; j++) {
                tempArray2[i][j] = salaryArray[i][j];
              }
            }

            // Buble Sort to store rowSums
            int [] rowSums = new int [tempArray2.length];
            for (int i = 0; i < tempArray2.length; i++) {
              for (int j = 0; j < tempArray2[0].length; j++) {
                rowSums[i] += tempArray2[i][j];
              }
            }

            //Buble Sort by Rows Sum (Lowest Value to Highest)
            int temp;
            int i = 0;
            for(int j = rowSums.length; j > 0; j--){
              boolean isSwap = false;
              for (i = 1; i < j; i++) {
                if(rowSums[i-1] > rowSums[i]) {
                  temp = rowSums[i-1];
                  rowSums[i-1] = rowSums[i];
                  rowSums[i] = temp;
                  isSwap = true;
                  //swaps rows in corresponding tempArray2 
                  int [] temp2 = tempArray2[i-1];
                  tempArray2[i-1] = tempArray2[i];
                  tempArray2[i] = temp2;
                }
              }

              if(!isSwap){
                break;
              }
            }  
            /** No Need.
            for (int k = 0; k < tempArray2.length; k++) {
            temp = tempArray2[i-1][k];
            tempArray2[i-1][k] = tempArray2[i][k];
            tempArray2[i][k] = temp;
          }
          */

            for (int b = 0; b < tempArray2.length; b++) {
            for (int c = 0; c < tempArray2[b].length; c++) {
              System.out.print(tempArray2[b][c] + " ");
            }
          }
          }

        public static void main(String[] args) {
            sortedArrayByRowTot();
        }
      }