SOJ 1180. Pasting Strings

 1 #include <iostream>
 2 #include <stack>
 3 #include <string>
 4 using namespace std;
 5 
 6 int main() {
 7     int begin, end;
 8     while (cin >> begin >> end, begin != -1 && end != -1) {
 9         string text;
10         cin.get(); getline(cin, text);
11         stack<string> prepend, append;
12         for (int cur = 0; cur < begin; ++cur) {
13             if (text[cur] == ‘<‘) {
14                 if (text[cur + 1] == ‘/‘) {
15                     prepend.pop(); append.pop();
16                 } else {
17                     int tail = cur + 1;
18                     while (text[tail] != ‘>‘) ++tail;
19                     string tag = text.substr(cur, tail - cur + 1);
20                     prepend.push(tag);
21                     append.push(tag.insert(1, "/"));
22                 }
23             }
24         }
25         for (int cur = begin; cur < end; ++cur) {
26             if (text[cur] == ‘<‘) {
27                 if (text[cur + 1] == ‘/‘) {
28                     append.pop();
29                 } else {
30                     int tail = cur + 1;
31                     while (text[tail] != ‘>‘) ++tail;
32                     string tag = text.substr(cur, tail - cur + 1);
33                     append.push(tag.insert(1, "/"));
34                 }
35             }
36         }
37         string ans = text.substr(begin, end - begin);
38         while (!prepend.empty()) {
39             ans = prepend.top() + ans; prepend.pop();
40         }
41         while (!append.empty()) {
42             ans += append.top(); append.pop();
43         }
44         cout << ans << endl;
45     }
46     return 0;
47 }