[Luogu] 外星密码

https://www.luogu.org/problemnew/show/P1928

沙比提

读清题目

#include <bits/stdc++.h>

using namespace std;
const int N = ;

int pre[N], hou[N];

string s;
string ss;
int main()
{
    cin >> s;
    if(s.find('[') == -) {
        cout << s;
        return ;
    }
    for(int T = ; T <= ; T ++){

        if(T != ) s = ss;
        int len = s.length(), last;
        if(s.find('[') == -) break;
        memset(hou, , sizeof(hou));
        bool flag;
        for(int i = ; i < len; i ++){
            if(s[i] == '[') {last = i; flag = ;}
            else if(s[i] == ']' && flag) {hou[last] = i; flag = ;}
        }
        ss.clear();
        for(int i = ; i < len; i ++){
            if(!hou[i]) {ss += s[i]; continue ;}
            int tot = , j;
            j = i + ;
            while(s[j] >= '' && s[j] <= ''){
                tot = tot *  + s[j] - '';
                j ++;
            }
            string s1;
            while(s[j] != ']') s1 += s[j ++];
            for(int k = ; k <= tot; k ++) ss += s1;
            i = hou[i];
        }
    }
    cout << ss;

    return ;
}