E-牛牛的加法

  • 模拟加法运算，需要进1的时候，不进位
  • 注意去掉前导0

代码如下:

#include<bits/stdc++.h>

using namespace std;

#define  mm(a,x) memset(a,x,sizeof a)
#define  mk make_pair
#define ll long long
#define pii pair<int,int>
#define inf 0x3f3f3f3f
#define lowbit(x) (x) & (-x)

string a,b;
vector<int > A,B;
vector<int > C;

int main() {
    cin >> a >> b;
    for(int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');
    for(int i = b.size() - 1; i >= 0; i -- ) B.push_back(b[i] - '0');
    int t = 0;
    for(int i = 0; i < A.size() || i < B.size(); i ++ ){
        if(i < A.size()) t += A[i];
        if(i < B.size()) t += B[i];
        C.push_back(t%10);
        t = 0;
    }
    while(C.size() > 1 && C.back() == 0) C.pop_back();
    for(int i = C.size() - 1; i >= 0; i -- ){
        cout<<C[i];
    }    
    return 0;
}