题解 | 游游的重组偶数

#include <iostream>
#include<string>
#include<algorithm>
#include<vector>
using namespace std;
int q;

int main() 
{
    cin >> q;

    while(q--)
    {
        int s;
        bool is = false;
        cin >> s;

        if(s % 2 == 0)
        {
            cout << s << endl;
            is = true;
            continue;
        }
        else 
        {
            vector<int> num;
            bool is1 = false;
            while(s > 0)
            {
                int temp = s % 10;
                num.push_back(temp);
                s /= 10;
            }
            int len = num.size();
            for(int i = 0;i <num.size();++i)
            {
                if(num[i] % 2 == 0)
                {
                    swap(num[i] , num[len - 1]);
                    is1 = true;
                    is = true;
                    break;
                }
            }

            if(is1)
            {
                for(int i = 0;i < num.size();++i)
                {
                    cout << num[i];
                }
                cout << endl;
            }

            
            
        }

        if(!is)
        {
            cout << -1 << endl;
        }

    }    
    
}
// 64 位输出请用 printf("%lld")