如何更有效地对矩阵进行排序？(c++)

Question

我正在尝试对矩阵进行排序，但我的代码似乎过长、复杂且效率低下。 我确信有更好、更有效的方法来对矩阵进行排序，但尽管我努力尝试，但我找不到它们。如果有人可以帮助我，我将非常感激

我尝试初始化一个数组

temp

将矩阵中的每个元素复制到其中，然后对数组进行排序（冒泡排序），然后将排序后的数组复制回矩阵。这个过程比我想象的要长。

int main()
{
    // Matrix initialization
    int matrix[row][col];
    for (int i = 0; i < row; i++)
        for (int j = 0; j < col; j++)
            cin >> matrix[i][j];

    // Building an array and copying the matrix elements to the array
    int temp[row* col];
    int nextRow = 0;
    for (int i = 0; i <= row* col; i++)
    {
        if (i - (col* nextRow) < row)
            temp[i] = matrix[nextRow][i - (col* nextRow)];
        else if (i - (col* nextRow) == row)
        { 
            i--;
            nextRow++;
        }
    }
    
    //Bubble sorting the array
    for (int i = 0; i + 1 < row * col; ++i)
    {
        for (int j = 0; j  + 1 < (row * col) - i; ++j)
        {
            if (temp[j] > temp[j + 1])
            {
                int t = temp[j];
                temp[j] = temp[j + 1];
                temp[j + 1] = t;
            }
        }
    }

    //Copying back the elements from the array to the matrix
    nextRow = 0;
    for (int i = 0; i < row * col; ++i)
    {
        if (i % row == 0)
            nextRow++;
        matrix[nextRow][i - (col * nextRow)] = temp[i];
    }
    return 0;
}

Answer 1

这是一个使用 std::sort 的示例。

#include <array>
#include <algorithm>
#include <iostream>

int main()
{
    // sizes of your matrix
    static constexpr std::size_t rows_v{ 5ul };
    static constexpr std::size_t cols_v{ 5ul };

    // initialize your matrix with values
    // I like using std::array (easier to pass around to functions) 
    
    //int matrix[rows_v][cols_v] // you can still use "C" style array, but I use std::array
    std::array<std::array<int, cols_v>, rows_v> matrix{{ // remove one bracket here if you use "C" style array
        {1,2,3,4,5},
        {9,6,4,3,1},
        {6,7,3,2,3},
        {9,4,6,2,3},
        {3,0,4,2,1}
    }};

    // range based for loop that will return
    // each row of the matrix one by one
    // each row will be a reference to a std::array<int, cols_v>
    // no need to type that, the compiler can figure out the type for you
    for (auto& row : matrix)
    {
        // sort each row from begin to end.
        // std::sort(std::begin(row),std::end(row)); // for "C" style array
        std::sort(row.begin(), row.end());
    }

    // then show the content
    // this time by const& since we are only going to output values 
    // not change them
    for (const auto& row : matrix)
    {
        for (const auto value : row)
        {
            std::cout << value << " ";
        }
        std::cout << "\n";
    }

    return 0;
}