P1305 新二叉树

#include<bits/stdc++.h>
using namespace std;
const int MAXN=30;
struct Node{
	char data;
	char left;
	char right;
};
map<char,Node> node;
void pretra(char root){
	if(root=='*') return;
	cout<<node[root].data;
	pretra(node[root].left);
	pretra(node[root].right);
}
int main()
{
	freopen("in.txt","r",stdin);
	int n;cin>>n;
	map<char,bool> mp;getchar();
	vector<char> st;
	for(int i=0;i<n;i++){
		char a,b,c;
		cin>>a>>b>>c;
		node[a].data=a;
		node[a].left=b;
		node[a].right=c;
		mp[b]=true;mp[c]=true;
		st.push_back(a);
		if(b!='*') st.push_back(b);
		if(c!='*') st.push_back(c);
		getchar();
	}
	char root='%';
	for(int i=0;i<st.size();i++){
		if(mp[st[i]]==false){
			root=st[i];break;
		}
	}
	pretra(root);
	return 0;
}