1 #define _CRT_SECURE_NO_WARNINGS
2
3 #include<cstdio>
4 #include<stack>
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 assigned
12 while (scanf("%d", &n) == 1 && n != 0) {
13 while (true) {
14 // the last line of the block contains just 0
15 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<int> s;
22 // assume an input array input[] containing 1, 2, ..., n in sequence, input[i] == i
23 // 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 }
