1 #define _CRT_SECURE_NO_WARNINGS 2  3 #include
     
       4 #include
      
        5 using namespace std; 6 const int MAXN = 1000 + 10; 7  8 int n, target[MAXN]; 9 10 int main() {11     // scanf() returns the number of input items matched and assigned12     while (scanf("%d", &n) == 1 && n != 0) {13         while (true) {14             // the last line of the block contains just 015             scanf("%d", &target[1]);16             if (target[1] == 0) { printf("\n"); break; }17 18             for (int i = 2; i <= n; i++)19                 scanf("%d", &target[i]);20 21             stack
       
         s;22             // assume an input array input[] containing 1, 2, ..., n in sequence, input[i] == i23             // A is the index of input[], and B is the index of target[]24             int A = 1, B = 1;25             bool ok = true;26             while (B <= n) {27                 if (A == target[B]){28                     A++;29                     B++;30                 } else if (!s.empty() && s.top() == target[B]){31                     s.pop();32                     B++;33                 } else if (A <= n){34                     s.push(A++);35                 } else {36                     ok = false;37                     break;38                 }39             }40 41             printf("%s\n", ok ? "Yes" : "No");42         }43     }44     return 0;45 }