压缩矩阵的转置：1、头文件。2、创建。3、初始化。4、打印。5、转置。

这篇博客介绍了如何初始化和操作压缩矩阵。通过`initCompressedMatrix`函数创建了一个压缩矩阵，并使用`printCompressedMatrix`展示其内容。此外，还详细讲解了矩阵转置的实现，通过`transposeCompressedMatrix`函数完成，该函数计算了新的偏移量并重新组织了元素。

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

typedef int elem;
//原矩阵的行、列、数据
typedef struct Triple{
    int i;
    int j;
    elem e;
}Triple,*TriplePtr;

typedef struct CompressedMatrix{
    int rows,columns,numElements;
    Triple* elements;
}CompressedMatrix,*CompressedMatrixPtr;

//初始化一个压缩矩阵 
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];
	}
	
	return resultPtr;
}


//打印压缩的矩阵 
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);
	}
}

//转置 
CompressedMatrixPtr transposeCompressedMatrix(CompressedMatrixPtr paraPtr){
	int i, tempColumn, tempPosition;
	int *tempColumnCounts = (int*)malloc(paraPtr->columns * sizeof(int));
	int *tempOffsets = (int*)malloc(paraPtr->columns * sizeof(int));
	
	//偏移量初始为0
	for(i = 0; i < paraPtr->columns; i ++){
		tempColumnCounts[i] = 0;
	}

	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));
	
	//扫描并计算偏移量 
	for(i = 0; i < paraPtr->numElements; i ++) {
		tempColumnCounts[paraPtr->elements[i].j] ++;
	}
	//第0行开始为0
	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]);
	}

	//再次扫描填充数据 
	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]++;
	}

	return resultPtr;
}