diff --git a/Yang/5.c b/Yang/5.c
new file mode 100644
index 0000000..2e8bb33
--- /dev/null
+++ b/Yang/5.c
@@ -0,0 +1,96 @@
+#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;
+}