按非降序排列n x m数组按行和列排列

Question

我想以非降序对输入数组进行行和列排序。我想当我试图转置我的数组时出现问题。我应该更改我的代码吗？

假设我们输入了这样的内容：

10 10 10 10
2  3  1  4
5  6  8  7

我想得到的输出：

1  2  3  4
5  6  7  8
10 10 10 10

输出即时消息（错误）：

1  2  3  0
5  6  7  0
10 10 10 0

int** sortRowCol(int **&A, int n, int m) {
    sortRow(A, n);
    int **T = transpose(A, n, m);
    sortRow(T, n);
    A = transpose(T, n, m);
    return A;
}

int **transpose(int **A, int n, int m) {
    int **T = new int *[m];
    for (size_t i = 0; i < m; ++i) {
        T[i] = new int[n];
        for (int j = 0; j < n; ++j)
            T[i][j] = A[j][i];
    }
    return T;
}

void sortRow(int **&A, int n) {
    for (size_t i = 0; i < n; ++i)
        std::sort(A[i], A[i] + n);
}
int main() {

    int n, m;
    std::cout << "Enter number of rows and columns: \n";
    std::cin >> n >> m;

    int **A = new int *[n];
    for (size_t i = 0; i < n; ++i)
        A[i] = new int[m];

    std::cout << "Fill array: \n";
    for (size_t i = 0; i < n; ++i)
        for (size_t j = 0; j < m; ++j)
            std::cin >> A[i][j];

    A = sortRowCol(A,n,m);
    printArray(A,n,m);
    deleteArray(A, n);
    return 0;
}

Answer 1

您的方法太复杂，而且存在内存泄漏。

和此功能

void sortRow(int **&A, int n) {
    for (size_t i = 0; i < n; ++i)
        std::sort(A[i], A[i] + n);
}

仅在平方矩阵的n等于m时可以工作。

首先对每个“行”进行排序，然后对指向“行”的指针数组进行排序要简单得多。

您在这里。

#include <iostream>
#include <iomanip>
#include <algorithm>

int main() 
{
    size_t n = 3;
    size_t m = 4;

    int **a = new int *[n];

    for ( size_t i = 0; i < n; i++ )
    {
        switch ( i )
        {
        case 0:         
            a[i] = new int[m] { 10, 10, 10, 10 };
            break;
        case 1:
            a[i] = new int[m] { 2,  3,  1,  4 };
            break;
        case 2:
            a[i] = new int[m] { 5,  6,  8,  7 };
        }           
    }

    for ( size_t i = 0; i < n; i++ )
    {
        for ( size_t j = 0; j < m; j++ )
        {
            std::cout << std::setw( 2 ) << a[i][j] << ' ';
        }
        std::cout << '\n';
    }

    putchar( '\n' );

    for ( size_t i = 0; i < n; i++ )
    {
        std::sort( a[i], a[i] + m );
    }

    std::sort( a, a + n, 
               [m]( const int *p1, const int *p2 ) 
               { 
                    return std::lexicographical_compare( p1, p1 + m, p2, p2 + m );
               } );

    for ( size_t i = 0; i < n; i++ )
    {
        for ( size_t j = 0; j < m; j++ )
        {
            std::cout << std::setw( 2 ) << a[i][j] << ' ';
        }
        std::cout << '\n';
    }

    putchar( '\n' );

    for ( size_t i = 0; i < n; i++ )
    {
        delete [] a[i];
    }

    delete [] a;

    return 0;
}

程序输出为

10 10 10 10 
 2  3  1  4 
 5  6  8  7 

 1  2  3  4 
 5  6  7  8 
10 10 10 10 

如果您还希望在对每一行进行排序之后对一列中的元素进行排序，则程序可以按照以下方式查找。

#include <iostream>
#include <iomanip>
#include <algorithm>

void sort_row( int a[], size_t n )
{
    std::sort( a, a + n );
}

int main() 
{
    size_t n = 3;
    size_t m = 4;

    int **a = new int *[n];

    for ( size_t i = 0; i < n; i++ )
    {
        switch ( i )
        {
        case 0:         
            a[i] = new int[m] { 20, 20, 10, 30 };
            break;
        case 1:
            a[i] = new int[m] { 10, 40, 10, 20 };
            break;
        case 2:
            a[i] = new int[m] { 20, 20, 10, 10  };
        }           
    }

    for ( size_t i = 0; i < n; i++ )
    {
        for ( size_t j = 0; j < m; j++ )
        {
            std::cout << std::setw( 2 ) << a[i][j] << ' ';
        }
        std::cout << '\n';
    }

    putchar( '\n' );

    for ( size_t i = 0; i < n; i++ )
    {
        sort_row( a[i], m );
    }

    int *tmp = new int[n];

    for ( size_t i = 0; i < m; i++ )
    {
        for ( size_t j = 0; j < n; j++ )
        {
            tmp[j] = a[j][i];
        }

        sort_row( tmp, n );

        for ( size_t j = 0; j < n; j++ )
        {
            a[j][i] = tmp[j];
        }
    }

    delete [] tmp;

    for ( size_t i = 0; i < n; i++ )
    {
        for ( size_t j = 0; j < m; j++ )
        {
            std::cout << std::setw( 2 ) << a[i][j] << ' ';
        }
        std::cout << '\n';
    }

    putchar( '\n' );

    for ( size_t i = 0; i < n; i++ )
    {
        delete [] a[i];
    }

    delete [] a;

    return 0;
}

程序输出为

20 20 10 30 
10 40 10 20 
20 20 10 10 

10 10 20 20 
10 10 20 30 
10 20 20 40