Rails (堆栈)<数据结构>

#include<iostream>
#include<stack>
#include<algorithm>
using namespace std;
int main ()
{
int N,data[1005],flag=1;
while(~scanf("%d",&N)&&N)
{
while(1)
{
for(int i=1;i<=N;i++){
flag=1;
scanf("%d",&data[i]);
if(data[1]==0){flag=0;break;}
}
if(!flag)
break;
else{
stack<int>st;
int A=1,B=1;
int ok=1;
while(B<=N){
if(A==data[B]){A++;B++;}
else if(!st.empty()&&st.top()==data[B]){st.pop();B++;}
else if(A<=N)st.push(A++);
else {ok=0;break;}
}
printf("%s\n",ok==1?"Yes":"No");
}
}
printf("\n");
}
return 0;
}