20pts求大佬条~QAQ

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int l2,l1,i,j,c[20010],b[20010],a[20010],mx;
	string z1,z2; 
	memset(c,0,sizeof(c));
	memset(a,0,sizeof(a));
	memset(b,0,sizeof(b));
	cin>>z1>>z2; 
	l1=z1.length();
	l2=z2.length();
	for(i=0;i<l1;i++)
		a[i]=z1[l1-1-i]-'0';
	for(i=0;i<l2;i++)
		b[i]=z2[l2-1-i]-'0';
	mx=l1+l2;
	for(i=0;i<l1;i++)
	{
		for(j=0;j<l2;j++)
		{
			c[i+j]+=b[j]*a[i];
			if(c[i+j]>=10)
			{
				c[i+j+1]+=c[i+j]/10;
				c[i+j]%=10;
			}
		}
		
	}
	while(c[mx]==0&&mx!=0)
		mx--;
	for(i=mx;i>=0;i--)
		cout<<c[i];
	return 0;
}