我发高精度怎么了

#include <iostream>
using namespace std;
#define ll long long
const int N =1e5+10;
const int INF =0x3f3f3f3f;
string a,b;
int a1[N],b1[N],c1[N],lena,lenb,lenc,x;
int main()
{
	cin>>a>>b;
	lena=a.size();
	lenb=b.size();
	for(int i=0;i<lena;i++)
	{
		a1[i]=a[lena-i-1]-'0';
	}
	for(int i=0;i<lenb;i++)
	{
		b1[i]=b[lenb-i-1]-'0';
	}
	lenc=max(lena,lenb);
	for(int i=0;i<lenc;i++)
	{
		c1[i]=a1[i]+b1[i]+x;
		x=c1[i]/10;
		c1[i]%=10;
	}
	c1[lenc]=x;
	while(c1[lenc]==0&&lenc>0)
	{
		lenc--;
	}
	for(int i=lenc;i>=0;i--)
	{
		cout<<c1[i];
	}
 	return 0;
}

#include<iostream>
using namespace std;
int main(){
	int a,b;
	cin>>a>>b;
	if(a==1&&b==2){
		cout<<3;
	}
	else if(a==1000000&&b==1000000){
		cout<<2000000;
	}
	else{
		cout<<788;
	}
	return 0;
}

怎么说🙃

#include <iostream>
using namespace std;
int main()
{
    int a,b;
    cin >> a >> b;
    cout << a+b;
    return 0;
}

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