题解 | #字符串合并处理#

#include <algorithm>
#include <iostream>
#include <bits/stdc++.h>
#include <vector>
using namespace std;

int main() {
   string s,s2;
   cin >> s >> s2;
   s += s2;
   vector<char> odd;
   vector<char> even;
   for(int i = 0; i<s.size(); i++){
        if(i%2 == 0){
            even.push_back(s[i]);
        }else{
            odd.push_back(s[i]);
        }
   }
   sort(even.begin(),even.end());
   sort(odd.begin(),odd.end());
   int idx1 = 0, idx2 = 0;
   for(int i = 0; i<s.size(); i++){
       if(i % 2 == 0){
         s[i] = even[idx1++];
       }else{
         s[i] = odd[idx2++];
       }

    bool flag = true;
       if(s[i] >= 'a' && s[i] <= 'f'){
            s[i] -= 'a'-10; 
       }else if(s[i] >= '0' && s[i] <='9'){
        s[i] -= '0';
       }else if(s[i] >= 'A' && s[i] <= 'F'){
        s[i] -= 'A'-10;
       }else{
        flag = false;
       }
        int num = s[i];

    if(flag){
        int res = 0;
        for(int i = 0; i<4; i++){
            res = res * 2 + num % 2;
            num = num/2;
        }
        if(res >= 10){
            s[i] = 'A' + res - 10;
        }else{
            s[i] = res + '0';
        }
    }
   }
    cout << s;
}
// 64 位输出请用 printf("%lld")