再DEV上测样例点是对的，提交却齐全wa了

#include <cmath>
#include <cstdio>
#include <cstring>  
#include <iostream>
using namespace std;
int a[10000];
string s1,s2;
void addd()
{
    int a1=s1.size(),a2=s2.size();
    for (int i=0;i<a1;i++)
      for (int j=0;j<a2;j++)
        a[a1-i+a2-j-1]+=(s1[i]-'0')*(s2[j]-'0');

    for (int i=1;i<=a1+a2;i++) { a[i+1]+=a[i]/10; a[i]%=10; }
    a[0]=a1+a2; while (a[a[0]]==0&&a[0]>1) a[0]--;
    }

int main()
{
    getline(cin,s1);
    getline(cin,s2);
    memset(a,0,sizeof(a));
    addd();
    for (int i=a[0];i>=1;i--) cout<<a[i];
    cout<<endl;
    return 0;
    }