稀疏矩阵的十字链表乘法

//cross.h

#include <iostream>
using namespace std;

struct Node
{
short row;
short col;
int num;
Node * right; //同一行的下一个元素
Node * down; //同一列的下一个元素

Node()
{
   row = col = -1;
   num = 0;
   right = down = NULL;
}
Node(short _row, short _col, int _val)
{
   row = _row;
   col = _col;
   num = _val;
   right = down = NULL;
}
};

class Cross
{
private:
int m_row; //行数
int m_col; //列数
Node ** pRow;
Node ** pCol;
Cross(){}
public:
Cross(int row, int col);
int GetRow() const
{
   return m_row;
}
int GetCol() const
{
   return m_col;
}

~Cross();
void GetChainFromMatrix(const int * arr);
void Add(int row, int col, int num);
void Multiplication(const Cross & multiplicator, Cross & result);
void GetMatrix(int * arr);
void Show();
};

//cross.cpp

#include "cross.h"

Cross::Cross(int row, int col):m_row(row), m_col(col)
{
pRow = new Node*[m_row];
for(int i = 0; i < m_row; ++i)
{
   pRow[i] = NULL;
}

pCol = new Node*[m_col];
for(/*int */i = 0; i < m_col; ++i)
{
   pCol[i] = NULL;
}
}

Cross::~Cross()
{
for(int i = 0; i < m_row; ++i)
{
   Node * temp = pRow[i];
   while(temp)
   {
    pRow[i] = temp->right;
    delete temp;
    temp = pRow[i];
   }
}
delete [] pRow;
delete [] pCol;
}

//此处arr的维数应和m_row,m_col相同,可通过GetRow,GetCol获得
void Cross::GetChainFromMatrix(const int * arr)
{
for(int i = 0; i < m_row; ++i)
{
   for(int j = 0; j < m_col; ++j)
   {
    if(arr[i * m_row + j] == 0) //如果是零元,则继续
     continue;

    Node * add = new Node(i, j, arr[i * m_row + j]);

   
    if(pRow[i])
    {
     Node * temp = pRow[i]; //链接到行上
     while(temp)
     {
      //此处排序,若按从左至右,从上至下的顺序进行,则已有序
      /*if(temp->right && temp->right->col > add->col)
      {
       add->right = temp->right;
       temp->right = add;
       break;
      }*/
     
      if(temp->right == NULL)
      {
       temp->right = add;
       break;
      }
      temp = temp->right;
     }
    }
    else
     pRow[i] = add;
   

    if(pCol[j])
    {
     Node * temp = pCol[j]; //链接到列上
     while(temp)
     {
     
      //此处排序,若按从左至右,从上至下的顺序进行,则已有序
      /*if(temp->down && temp->down->row > add->row)
      {
       add->down = temp->down;
       temp->down = add;
       break;
      }*/
     
      if(temp->down == NULL)
      {
       temp->down = add;
       break;
      }
      temp = temp->down;
     }
    }
    else
     pCol[j] = add;

   }
}
}

void Cross::Add(int row, int col, int num)
{

Node * add = new Node(row, col, num);

if(pRow[row])
{
   Node * temp = pRow[row]; //链接到行上
   while(temp)
   {
    //此处排序,若按从左至右,从上至下的顺序进行,则已有序
    if(temp->right && temp->right->col > add->col)
    {
     add->right = temp->right;
     temp->right = add;
     break;
    }
   
    if(temp->right == NULL)
    {
     temp->right = add;
     break;
    }
    temp = temp->right;
   }
}
else
   pRow[row] = add;

if(pCol[col])
{
   Node * temp = pCol[col]; //链接到列上
   while(temp)
   {
   
    //此处排序,若按从左至右,从上至下的顺序进行,则已有序
    if(temp->down && temp->down->row > add->row)
    {
     add->down = temp->down;
     temp->down = add;
     break;
    }
   
    if(temp->down == NULL)
    {
     temp->down = add;
     break;
    }
    temp = temp->down;
   }
}
else
   pCol[col] = add;
}

void Cross::Multiplication(const Cross & multiplicator, Cross & crossResult)//外部确保此处crossResult中没有数据
{
for(int i = 0; i < m_row; ++i)
{
   for(int j = 0; j < multiplicator.m_col; ++j)
   {
    int count = 0; //crossResult中(i, j)位置的值
    Node * pR = pRow[i];
    Node * pC = multiplicator.pCol[j];
    while(pR && pC)
    {
     if(pR->col == pC->row)
     {
      count += (pR->num * pC->num);
      pR = pR->right;
      pC = pC->down;
     }
     else if(pR->col < pC->row)
     {
      pR = pR->right;
     }
     else
     {
      pC = pC->down;
     }
    }// end of while
    if(count > 0)
    {
     crossResult.Add(i, j, count);
    }
   }
}
}

void Cross::GetMatrix(int * arr)
{
memset(arr, 0, sizeof(int) * m_row * m_col);
for(int i = 0; i < m_row; ++i)
{
   Node * temp = pRow[i];
   while(temp)
   {
    arr[i * m_row + temp->col] = temp->num;
    temp = temp->right;
   }
}
}

void Cross::Show()
{
for(int i = 0; i < m_row; ++i)
{
   Node * temp = pRow[i];
   while(temp)
   {
    cout << "(" << temp->row << "," << temp->col << "," << temp->num << ")" << '\t';
    temp = temp->right;
   }
   cout << endl;
}
}

//mm.cpp

#include "cross.h"

int main()
{
int num1[5][5] = {
   {1,0,0,0,0},
   {0,2,0,0,0},
   {0,3,0,0,0},
   {0,0,0,4,0},
   {0,0,0,0,5}};

int num2[5][5] = {
   {1,0,0,0,0},
   {2,0,0,0,0},
   {0,3,0,0,0},
   {0,0,0,0,4},
   {0,0,5,0,0}};

int num3[5][5];

Cross cr1(5, 5);
cr1.GetChainFromMatrix((const int *)num1);
cr1.Show();
cout << endl;

Cross cr2(5, 5);
cr2.GetChainFromMatrix((const int *)num2);
cr2.Show();
cout << endl;

Cross cr3(5, 5);
cr1.Multiplication(cr2, cr3);
cr3.Show();
cout << endl;

cr3.GetMatrix((int *)num3);

for(int i = 0; i < 5; ++i)
{
   for(int j = 0; j < 5; ++j)
   {
    cout << num3[i][j] << '\t';
   }
   cout << endl;
}

return 0;
}