数据结构----二维数组与矩阵乘法、压缩矩阵的转置

二维数组与矩阵乘法的完整代码

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>

#define ROWS 4
#define COLUMNS 5

/*
Two dimensional array.
*/

typedef struct TwoDArray{
	int rows;
	int columns;
	int** elements;
}TwoDArray,*TwoDArrayPtr;

/*
Two dimensional array.
*/

typedef struct TwoDStaticArray{
	int rows;
	int columns;
	int elements[ROWS][COLUMNS];
}TwoDStaticArray,*TwoDStaticArrayPtr;

TwoDArrayPtr initTwoDArray(int paraRows,int paraColumns){
	int i;
	TwoDArrayPtr resultPtr=(TwoDArrayPtr)malloc(sizeof(struct TwoDArray));
	resultPtr->rows=paraRows;
	resultPtr->columns=paraColumns;
	resultPtr->elements=(int**)malloc(paraRows * sizeof(int*));
	for(i=0;i<paraRows;i++){
		resultPtr->elements[i]=(int*)malloc(paraColumns * sizeof(int));
	}//of for i
	
	return resultPtr;
}//of initTwoDArray

/*
Randomize the data of the array.
*/

void randomizeTwoDArray(TwoDArrayPtr paraPtr,int paraLowerBound,int paraUpperBound){
	int i,j;
	for(i=0;i<paraPtr->rows;i++){
		for(j=0;j<paraPtr->columns;j++){
			paraPtr->elements[i][j]=rand()%(paraUpperBound-paraLowerBound)+paraLowerBound;
		}//of for j
	}//of for i
}//of randomizeTwoDArray

/*
Print the array.
*/

void printTwoDArray(TwoDArrayPtr paraPtr){
	int i,j;
	for(i=0;i<paraPtr->rows;i++){
		for(j=0;j<paraPtr->columns;j++){
			printf("%d, ",paraPtr->elements[i][j]);
		}//of for j
		printf("\r\n");
	}//of for i
}//of printTwoDArray

/*
Matrix Multiply.
*/

TwoDArrayPtr matrixMultiply(TwoDArrayPtr paraPtr1,TwoDArrayPtr paraPtr2){
	int i,j,k,sum;
	if(paraPtr1->columns!=paraPtr2->rows){
		printf("Matrices cannot be multiplied.\r\n");
		return NULL;
	}//of if
	
	TwoDArrayPtr resultPtr=initTwoDArray(paraPtr1->rows,paraPtr2->columns);
	
	for(i=0;i<paraPtr1->rows;i++){
		for(j=0;j<paraPtr2->columns;j++){
			sum=0;
			for(k=0;k<paraPtr1->columns;k++){
				sum+=paraPtr1->elements[i][k] * paraPtr2->elements[k][j];
			}//of for k
			resultPtr->elements[i][j]=sum;
			printf("sum = %d, ",sum);
		}//of for j
	}//of for j
	
	return resultPtr;
}//of matrixMultiply

/*
Test the generation of the 2D array.
*/
void TwoDArrayTest(){
	TwoDArrayPtr tempPtr1,tempPtr2,tempPtr3;
	tempPtr1=initTwoDArray(3,2);
	randomizeTwoDArray(tempPtr1,1,5);
	printf("The first matrix:\r\n");
	printTwoDArray(tempPtr1);
	
	tempPtr2=initTwoDArray(2,4);
	randomizeTwoDArray(tempPtr2,4,9);
	printf("The second matrix:\r\n");
	printTwoDArray(tempPtr2);
	
	tempPtr3=matrixMultiply(tempPtr1,tempPtr2);
	printf("The result:\r\n");
	printTwoDArray(tempPtr3);
}//of TwoDArrayTest

/*
Intialize the two-dimensional array.
*/

TwoDStaticArray initTwoDStaticArray(){
	int i,j;
	TwoDStaticArrayPtr resultPtr=(TwoDStaticArrayPtr)malloc(sizeof(struct TwoDStaticArray));
	resultPtr->rows=ROWS;
	resultPtr->columns=COLUMNS;
	for(i=0;i<ROWS;i++){
		for(j=0;j<COLUMNS;j++){
			resultPtr->elements[i][j]=i*10+j;
			//print their addresses.
			printf("(%d, %d): %d ",i,j,&(resultPtr->elements[i][j]));
		}//of for j
	}//of for i
	
	return resultPtr;
}//of initTwoDStaticArray

/*
The entrance.
*/

int main(){
	TwoDArrayTest();
	TwoDStaticArrayPtr tempPtr=initTwoDStaticArray();
	
	return 1;
}//of main

运行结果

转置矩阵的完整代码

#include <stdio.h>
#include <malloc.h>

typedef int elem;

/**
 * A triple for row index, column index, and data.
 */
typedef struct Triple{
    int i;
    int j;
    elem e;
} Triple, *TriplePtr;

/**
 * A triple for row index, column index, and data.
 */
typedef struct CompressedMatrix{
    int rows,columns,numElements;
    Triple* elements;
} CompressedMatrix, *CompressedMatrixPtr;

/**
 * Initialize a compressed matrix.
 */
CompressedMatrixPtr initCompressedMatrix(int paraRows, int paraColumns, int paraElements, int** paraData){
	int i;
	CompressedMatrixPtr resultPtr = (CompressedMatrixPtr)malloc(sizeof(struct CompressedMatrix));
	resultPtr->rows = paraRows;
	resultPtr->columns = paraColumns;
	resultPtr->numElements = paraElements;
	resultPtr->elements = (TriplePtr)malloc(paraElements * sizeof(struct Triple));

	for(i = 0; i < paraElements; i ++){
		resultPtr->elements[i].i = paraData[i][0];
		resultPtr->elements[i].j = paraData[i][1];
		resultPtr->elements[i].e = paraData[i][2];
	}//Of for i

	return resultPtr;
}// Of initCompressedMatrix

/**
 * Print the compressed matrix.
 */
void printCompressedMatrix(CompressedMatrixPtr paraPtr){
	int i;
	for(i = 0; i < paraPtr->numElements; i ++){
		printf("(%d, %d): %d\r\n", paraPtr->elements[i].i, paraPtr->elements[i].j, paraPtr->elements[i].e);
	}//Of for i
}// Of printCompressedMatrix

/**
 * Transpose a compressed matrix.
 */
CompressedMatrixPtr transposeCompressedMatrix(CompressedMatrixPtr paraPtr){
	//Step 1. Allocate space.
	int i, tempColumn, tempPosition;
	int *tempColumnCounts = (int*)malloc(paraPtr->columns * sizeof(int));
	int *tempOffsets = (int*)malloc(paraPtr->columns * sizeof(int));
	for(i = 0; i < paraPtr->columns; i ++){
		tempColumnCounts[i] = 0;
	}//Of for i

	CompressedMatrixPtr resultPtr = (CompressedMatrixPtr)malloc(sizeof(struct CompressedMatrix));
	resultPtr->rows = paraPtr->columns;
	resultPtr->columns = paraPtr->rows;
	resultPtr->numElements = paraPtr->numElements;

	resultPtr->elements = (TriplePtr)malloc(paraPtr->numElements * sizeof(struct Triple));
	
	//Step 2. One scan to calculate offsets.
	for(i = 0; i < paraPtr->numElements; i ++) {
		tempColumnCounts[paraPtr->elements[i].j] ++;
	}//Of for i
	tempOffsets[0] = 0;
	for(i = 1; i < paraPtr->columns; i ++){
		tempOffsets[i] = tempOffsets[i - 1] + tempColumnCounts[i - 1];
		printf("tempOffsets[%d] = %d \r\n", i, tempOffsets[i]);
	}//Of for i

	//Step 3. Another scan to fill data.
	for(i = 0; i < paraPtr->numElements; i ++) {
		tempColumn = paraPtr->elements[i].j;
		tempPosition = tempOffsets[tempColumn];
		resultPtr->elements[tempPosition].i = paraPtr->elements[i].j;
		resultPtr->elements[tempPosition].j = paraPtr->elements[i].i;
		resultPtr->elements[tempPosition].e = paraPtr->elements[i].e;

		tempOffsets[tempColumn]++;
	}//Of for i

	return resultPtr;
}//Of transposeCompressedMatrix

/**
 * Test the compressed matrix.
 */
void compressedMatrixTest(){
	CompressedMatrixPtr tempPtr1, tempPtr2;
	int i, j, tempElements;

	//Construct the first sample matrix.
	tempElements = 4;
	int** tempMatrix1 = (int**)malloc(tempElements * sizeof(int*));
	for(i = 0; i < tempElements; i ++){
		tempMatrix1[i] = (int*)malloc(3 * sizeof(int));
	}//Of for i

	int tempMatrix2[4][3] = {{0, 0, 2}, {0, 2, 3}, {2, 0, 5}, {2, 1, 6}};
	for(i = 0; i < tempElements; i ++){
		for(j = 0; j < 3; j ++) {
			tempMatrix1[i][j] = tempMatrix2[i][j];
		}//Of for j
	}//Of for i
	
	tempPtr1 = initCompressedMatrix(2, 3, 4, tempMatrix1);

	printf("After initialization.\r\n");
	printCompressedMatrix(tempPtr1);

	tempPtr2 = transposeCompressedMatrix(tempPtr1);
	printf("After transpose.\r\n");
	printCompressedMatrix(tempPtr2);
}// Of main

/**
 * The entrance.
 */
int main(){
	compressedMatrixTest();

	return 1;
}// Of main

图示

 

 

 

运行结果