思路：

貪心亂搞。

實現：

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 vector<vector<int>> v;
 4 int main()
 5 {
 6     string s;
 7     while (cin >> s)
 8     {
 9         set<int> x, y;
10         for (int i = 0; i < v.size(); i++) v[i].clear();
11         bool no_ans = false
 
;
12         for (int i = 0; i < s.length(); i++)
13         {
14             if (s[i] == ‘1‘)
15             {
16                 if (x.empty()) { no_ans = true; break; }
17                 auto be = x.begin(); 
18                 int tmp = *be;
19                 x.erase(be);
20                 v[tmp].push_back(i);
 
21                 y.insert(tmp);
22             }
23             else
24             {
25                 if (y.empty()) { v.push_back(vector<int>()); y.insert(v.size() - 1); }
26                 auto be = y.begin(); 
27                 int tmp = *be;
28                 y.erase(be);
29                 v[tmp].push_back(i);
 
30                 x.insert(tmp);
31             }
32         }
33         for (int i = 0; i < v.size(); i++)
34         {
35             if (v[i].size() && s[v[i].back()] == ‘1‘) no_ans = true;
36         }
37         if (no_ans) cout << -1 << endl;
38         else 
39         {
40             cout << v.size() << endl;
41             for (int i = 0; i < v.size(); i++)
42             {
43                 cout << v[i].size() << " ";
44                 for (int j = 0; j < v[i].size(); j++)
45                 {
46                     cout << v[i][j] + 1 << " ";
47                 }
48                 cout << endl;
49             }
50         }
51     }
52     return 0;
53 }

CF949A/950C Zebras