#include<bits/stdc++.h>
#define maxn 5010
using namespace std;
int a[maxn],b[maxn],c[maxn],la,lb;
int main(){
	string A,B;
	cin>>A>>B;
	la=A.length(),lb=B.length();
	for (int i=la-1;i>=0;i--) a[la-i]=A[i]-'0';
	for (int i=lb-1;i>=0;i--) b[lb-i]=B[i]-'0';
	for (int i=1;i<=la;i++)
		for (int j=1;i<=lb;j++)
			c[i+j-1]+=a[i]*b[j];
	int len=la+lb;
	for (int i=1;i<=len;i++){
		c[i+1]+=c[i]/10;
		c[i]%=10;
	}
	for (;!c[len];)
		len--;
	for (int i=max(1,len);i>=1;i--)
		cout<<c[i];
	return 0;
}

各位大佬帮忙改一下代码