题解

#include<bits/stdc++.h>
using namespace std;
int main()
{
    string n;
    cin >> n;
    string num = n;
    bool flag = true;
    if (n[0] == '-')
    {
        num = n.substr(1, n.size() - 1);
        flag = false;
    }
    while (num.size() >= 1 && num[num.size() - 1] == '0')
    {
        num.pop_back();
    }
    reverse(num.begin(), num.end());
    if (num.empty())
    {
        cout << 0;
    }
    else
    {
        if (flag)
        {
            cout << num;
        }
        else
        {
            cout << '-' << num;
        }
    }
    return 0;
}