80分最后一个点错了

#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int a[505],b[505],c[505];
int main(){ 
	cin>>s1>>s2;
	for(int i=0;i<s1.size();i++)a[i+1]=s1[i]-'0';
	for(int i=0;i<s2.size();i++)b[i+1]=s2[i]-'0';
	reverse(a+1,a+s1.size()+1);
	reverse(b+1,b+s1.size()+1);
	int lon=0;
	for(int i=1;i<=max(s1.size(),s2.size());i++){
		c[i]+=a[i]+b[i];
		if(c[i]>=10&&i==max(s1.size(),s2.size())){
			lon+=2;
			c[i+1]+=c[i]/10;
			c[i]%=10;
			continue;
		}
		c[i+1]+=c[i]/10;
		c[i]%=10;
		lon++;
	}
	for(int i=lon;i>=1;i--)cout<<c[i];
	return 0;
} 

这是错的那一组数据 350204156568812004512541458715942878921069349854678 5120132301230048014584016540526804565814706519846494321001345794503242112976563432120

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