求dalao帮助，35WA了，但是我用3的数据本地测是对的

#include <bits/stdc++.h>
#define maxn 1001
using namespace std;
int main( ){
	string a,b;
	cin>>a>>b;
	int numa[maxn],numb[maxn];
	int la,lb;
	la=a.size( );lb=b.size( );
	for(register int i=1;i<=la;i++) numa[i]=a[la-i]-'0';
	for(register int i=1;i<=lb;i++) numb[i]=b[lb-i]-'0';
	int numc[maxn]={0},lc;
	lc=max(la,lb);
	for(register int i=1;i<=lc;i++){
		numc[i]=numa[i]+numb[i]+numc[i];
		if(numc[i]>=10) numc[i+1]=numc[i]/10,numc[i]=numc[i]%10;
	}
	if(numc[lc+1]) lc++;
	string ans;
	for(register int i=lc;i>=1;i--) ans+=numc[i]+'0';
	cout<<ans; 
	return 0;
}