diff --git a/4.c b/4.c
new file mode 100644
index 0000000..45c5314
--- /dev/null
+++ b/4.c
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctime>
+#include <iostream>
+#include <ostream>
+#include <arm_neon.h>
+#define SIZE 1024
+int main(){
+	void matmul_optimized(float **A,float **B,float **C,int n);
+	int i,j,n;
+	float **A=new float*[n];
+	float **B=new float*[n];
+	float **C=new float*[n];
+	for(i=0;i<n;i++){
+		A[i]=new float[n];
+		B[i]=new float[n];
+		C[i]=new float[n];
+	}
+	for(i=0;i<n;i++){
+		for(j=0;j<n;j++){
+			A[i][j]=rand()%100;
+			B[i][j]=rand()%100;
+		}
+	}
+	clock_t start=clock();
+	matmul_optimized(A,B,C,SIZE);
+	clock_t end=clock();
+    std::cout<<"优化稠密矩阵乘法时间："<<double(end-start)/CLOCKS_PER_SEC<<"秒"<<std::endl; 
+	for(i=0;i<n;i++){
+		delete[] A[i];
+		delete[] B[i];
+		delete[] C[i];
+	}
+	delete[] A;
+	delete[] B;
+	delete[] C;
+}
+void matmul_optimized(float **A,float **B,float **C,int n){
+	int i,j,k;
+	for(i=0;i<n;i++){
+		for(j=0;j<n;j++){
+			float32x4_t vecC=vdupq_n_f32(0.0);
+			for(k=0;k<n;k+=4){
+				float32x4_t vecA=vld1q_f32(&A[i][j]);	
+				float32x4_t vecB=vld1q_f32(&B[i][j]);
+				vecC=vmlap_f32(vecC,vecA,vecB);
+				C[i][j]=vgetq_lane_f32(vecC,0)+vgetq_lane_f32(vecC,1)+vgetq_lane_f32(vecC,2)+vgetq_lane_f32(vecC,3);
+			}
+		}
+	}
+}
+