对于一个给定的含有加减乘的中缀表达式，可以任意加括号，排序输出所有得到的答案

#include<bits/stdc++.h>
using namespace std;
string s;
int n;
vector<int> work(string str){
    vector<int>tmp;
    int l = str.length();
    bool flag = 0;
    for(int i = 0; i < l; i++){
        if(!(isdigit(s[i]))){
            flag = 1;
            auto t1 = work(str.substr(0, i));
            auto t2 = work(str.substr(i + 1, l - i));
            for(auto x: t1)
                for(auto y: t2){
                    if(str[i] == '+') tmp.push_back(x + y);
                    if(str[i] == '-') tmp.push_back(x - y);
                    if(str[i] == '*') tmp.push_back(x * y);
                }
        }

    }
    if(!flag){
        int now = 0;
        for(int i = 0; i < l; i++){
            now = now * 10 + str[i] - '0';
        }
        tmp.push_back(now);
    }
    return tmp;
}
int main(){
    cin >> s;
    // n = strlen(s);
    vector<int>ans = work(s);
    sort(ans.begin(), ans.end());
    for(auto x: ans){
        cout<<x<<endl;
    }
    // work(s);    
}