答案114514

#include<bits/stdc++.h>
using namespace std;
string addition(string a,string b){
string c(max(a.length(),b.length())+1,0);
int i=a.length()-1,j=b.length()-1,k=c.length()-1;
while(i>=0||j>=0){
int A=0,B=0;
if(i>=0) A=a[i]-'0';
if(j>=0) B=b[j]-'0';
int sum=A+B;
c[k]+=sum;
if(c[k]>=10){
c[k-1]+=1;
c[k]-=10;
}
i--,j--,k--;
}
for(int i=0;i<c.length();i++){
c[i]+='0';
}
while(c.length()>1&&c.front()=='0') c.erase(c.begin());
return c;
}
int main(){
string a,b;
cin>>a>>b;
cout<<addition(a,b);
return 0;
}