题解 | 字符串排序

#include <iostream>
#include <vector>
using namespace std;

int main() {
    string s;
    vector<char> arr;
    getline(cin, s);

    for (int i = 0; i < 26; ++i) {
        for (char& j : s) {
            if ( (j - 'a' == i) || (j - 'A' == i))
                arr.push_back(j);//将符合规则字母先后放进arr
        }
    }

    for (int i = 0; i < s.size(); ++i) {
        if ( (s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z') )
            continue;
        else
            arr.insert(arr.begin() + i, s[i]); //非字母按原先顺序加入到arr里
    }


    for (char str : arr) {
        cout << str;
    }
    return 0;
}