题解

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
string s1,s2;
const int N = 1e6+5;
int len1,len2,len,i,j;
int a[N];
int b[N];
int c[N];
int main(){
    cin>>s1>>s2;
    len1 = s1.length();
    len2 = s2.length();
    len = max(len1,len2);
    for(i = 0;i < len1;i++){
		a[i] = s1[len1-1-i] - '0';
	}
	for(i = 0;i < len2;i++){
		b[i] = s2[len2-1-i] - '0';
	}
	for(i = 0;i < len;i++){
		c[i] += a[i] + b[i];
		c[i+1] += c[i] / 10;
		c[i] %= 10;
	}
	if(c[len]){
		len++;
	}
	for(i = len-1;i >= 0;i--){
		cout<<c[i];
	}
	return 0; 
}