pata1086

1、全局变量n不要再在main里面重复定义；

2、后序遍历的时候记得最后要跳出函数；

#include<iostream> 
#include<stack>
#include<cstdio>
#include<cstring>
#include<vector>
using namespace std;
const int maxn=50;
struct node{
	int data;
	node* lc;
	node* rc;
};
int pre[maxn];
int in[maxn];
int pos[maxn];
int n;
//vector<int> pre,in;
node* create(int prel,int prer,int inl,int inr){
	if(prel>prer){
		return NULL;
	}
	node *root=new node;
	root->data=pre[prel];
	int k=0;
	for(int i=inl;i<=inr;i++){
		if(in[i]==pre[prel]){
			k=i;
			break;
		}
	}
	int templ=k-inl;
	root->lc=create(prel+1,prel+templ,inl,k-1);
	root->rc=create(prel+1+templ,prer,k+1,inr);
	return root;
}
int num=0;
void postraverse(node* a){
	if(a==NULL){
		return;
	}
	postraverse(a->lc);
	postraverse(a->rc);
	num++;
	if(num<n)
	printf("%d ",a->data);
	else
	printf("%d",a->data);
}
int main()
{
	#ifdef ONLINE_JUDGE
	#else
	freopen("in.txt","r",stdin);
	//freopen("out.txt","w",stdout);
	#endif
	//int n;
	cin>>n;
	stack<int> s;
	int front;
	char ss[5];
	int precount=0,incount=0;
	for(int i=0;i<2*n;i++){
		//cin>>ss;
		scanf("%s",ss);
		if(strcmp(ss,"Push")==0){
			cin>>front;
			//pre.push_back(front);
			pre[precount++]=front;
			s.push(front);
			
		}else{
			//in.push_back(s.top());
			in[incount++]=s.top();
			s.pop();
		}
	}
	node* root=create(0,n-1,0,n-1);
	postraverse(root);
	return 0;
}