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

typedef struct {
    int* values;      
    int* rowIndex;    
    int* colIndex;    
    int nonZeroCount; 
} SparseMatrix;

void sparseMatmul(SparseMatrix* A, SparseMatrix* B, SparseMatrix* C) {
    int currentIndex = 0;
    int i, j;
    for (i = 0; i < A->nonZeroCount; i++)
    {
        int rowA = A->rowIndex[i];
        int colA = A->colIndex[i];
        float valueA = A->values[i];
        for (j = 0; j < A->nonZeroCount; j++)
        {
            int rowB = B->rowIndex[j];
            int colB = B->colIndex[j];
            float valueB = B->values[j];
            if (colA == rowB)
            {
                float product = valueA * valueB;
                int found = 0;
                int k;
                for (k = 0; k < currentIndex; k++)
                {
                    if (C->rowIndex[k] == rowA && C->colIndex[k] == colB){
                        C->values[k] += product;
                        found = 1;
                        break;
                    }
                }
                if (!found)
                {
                    C->values[currentIndex] = product;
                    C->rowIndex[currentIndex] = rowA;
                    C->colIndex[currentIndex] = colB;
                    currentIndex++;
                }
            }
        }
    }
    C->nonZeroCount = currentIndex;
}

void free_matrix(SparseMatrix* matrix) {
    free(matrix->values);
    free(matrix->rowIndex);
    free(matrix->colIndex);
}

int main() {
    SparseMatrix A = {
        .values = (int[]){1, 2, 3, 4, 5},
        .rowIndex = (int[]){0, 0, 1, 2, 2},
        .colIndex = (int[]){0, 2, 1, 0, 2},
        .nonZeroCount = 5
    };
    
    SparseMatrix B = {
        .values = (int[]){6, 8, 7, 9},
        .rowIndex = (int[]){0, 2, 1, 2},
        .colIndex = (int[]){0, 0, 1, 2},
        .nonZeroCount = 4
    };

    SparseMatrix C;
    C.values = (int*)malloc(A.nonZeroCount * B.nonZeroCount * sizeof(int));
    C.rowIndex = (int*)malloc(A.nonZeroCount * B.nonZeroCount * sizeof(int));
    C.colIndex = (int*)malloc(A.nonZeroCount * B.nonZeroCount * sizeof(int));
    C.nonZeroCount = 0;

    clock_t start_time = clock();

    sparseMatmul(&A, &B, &C);

    clock_t end_time = clock();
    double time = (double)(end_time - start_time) / CLOCKS_PER_SEC;
    printf("%f\n", time);
    
    int i;
    for (i = 0; i < C.nonZeroCount; ++i) {
        printf("C[%d][%d] = %d\n", C.rowIndex[i], C.colIndex[i], C.values[i]);
    }

    free_matrix(&A);
    free_matrix(&B);
    free_matrix(&C);

    return 0;
}