20分求调

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

int n;
vector<string>res;

int check(int tmp)
{
    int i;
    for(i = 1; ; i ++)
    {
        if(tmp >> i == 0)break;
    }
    return i - 1;
}

void dfs(int n)
{
    int tmp = n & -n;
    if(tmp != 0)
    {
        //cout << tmp << endl;
        dfs(n - tmp);
        res.push_back("(");
        int t = check(tmp);
        if(t > 2)dfs(t);
        else res.push_back(to_string(t));
        res.push_back(")");
    }
}


int main()
{
    cin>>n;
    dfs(n);
    res.push_back("");
    //for(int i = 0; i < res.size(); i ++)cout << res[i];
    for(int i = 0; i < res.size(); i ++)
    {
        if(res[i] == "(" && res[i + 1] == "1")
        {
            cout << 2 << '+';
            i += 2;
        }
        else 
        {
            if(res[i] == "(")cout << 2;
            if(res[i] != "1")cout << res[i];
            if(res[i] == ")" && res[i + 1] != ")" && res[i + 1] != "")
            cout << '+';
        }
    }
}