ZOJ 1259 Rails

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<stack>
 4 using namespace std;
 5 int goal[1005];
 6 int d[1005];
 7 stack<int>s;
 8 int main()
 9 {
10     freopen("input.txt","r",stdin);
11     int n;
12     for(int i = 0; i <= 1000; i++)
13         d[i] = i;
14     while(cin>>n && n)
15     {
16         while(cin>>goal[1] && goal[1])
17         {
18             while(!s.empty())
19                 s.pop();
20             for(int i = 2; i <= n; i++)
21                 cin>>goal[i];
22             int i = 2;
23             int pos = 1;
24             s.push(d[1]);
25             while(pos <= n && i <= n+1)
26             {
27                 if(s.empty() || s.top() != goal[pos])
28                 {
29                     s.push(d[i]);
30                     i++;
31                 }
32                 else if(s.top() == goal[pos])
33                 {
34                     s.pop();
35                     pos++;
36                 }
37                 else break;
38             }
39             if(s.empty())
40                 cout<<"Yes"<<endl;
41             else cout<<"No"<<endl;
42 
43         }
44         cout<<endl;
45     }
46     return 0;
47 }