牛客小白月赛30E

E 模拟 B站讲解https://www.bilibili.com/video/BV1GT4y1M78d?p=3

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
//typedef __int128 INT;
typedef double db;
typedef vector<int> vii;
typedef vector<ll> vll;
typedef pair<int,int> PII;
#define so sizeof
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define fi first
#define se second
#define mp make_pair
#define ub upper_bound
const db esp=1e-5;
const int N=2e5+10,M=2e5+10,Max=500,inf=0x3f3f3f3f,mod=998244353;
const ll INF=0x3f3f3f3f3f3f3f3f;

string a,b;
vii res;


void work(){
    cin>>a>>b;
    reverse(a.begin(),a.end());
    reverse(b.begin(),b.end());
    for(int i=0;;i++){
        if(i>=a.size()){
            for(;i<b.size();i++)
                res.pb(b[i]-'0');
            break;
        }else if(i>=b.size()){
            for(;i<a.size();i++)
                res.pb(a[i]-'0');
            break;
        }
        int t=(a[i]-'0')+(b[i]-'0'); t%=10;
        res.pb(t);
    }
    while(res.back()==0&&res.size()) res.ppb();
    reverse(res.begin(),res.end());
    if(res.size()==0){
        puts("0"); return ;
    }
    for(auto i:res)
        cout<<i;

    return ;
}


int main(){
        work();
    return 0;
}