数据结构：栈 - UVA 514 - Rails

 1  #include <cstdio>
 2  #include <stack>
 3  using namespace std;
 4  const int MAXN = 1000 + 10;
 5  int n, target[MAXN];
 6  int main(){
 7      while (scanf("%d",&n) && n) {
 8          while (scanf("%d",&target[1]) && target[1]) {
 9          stack<int> s;
10          int A = 1, B = 1;
11          int ok = 1;
12          if(target[1] == 0)
13              continue;
14          for (int i = 2; i <= n; i++) {
15              scanf("%d",&target[i]);
16          }
17          while (B <= n) {
18              if (A == target[B]) {
19                  A++; B++; // 正常出
20              }else if(!s.empty() && s.top() == target[B]){
21                  s.pop(); B++; // 从栈出
22              }else if(A <= n){ // 入栈
23                  s.push(A++);
24              }else{ 
25                  ok = 0;
26                  break;
27              }
28          }
29          printf("%s\n",ok ? "Yes":"No");
30          }
31          printf("\n");
32      }
33      return 0;
34  }