699 - The Falling Leaves

感觉这个题目就是在考察非递归先序建树，首先将所有的数据全部读入进来，然后利用栈非递归建树。将根节点所在的标志记为0，如果同时如果从当前节点向左，则相应的标志减一，如果是向右，则相应的标志加一，同时建立相应的标志到该标志的“总数”的映射，最后输出即可。对每个节点，设置一个pos，来记录相应的标志，具体的实现见源代码：

#include<iostream>
#include<vector>
#include<string>
#include<set>
#include<stack>
#include<queue>
#include<map>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<sstream>
using namespace std;

typedef struct node{
	int val;
	struct node* left, *right;
	int pos;
	node(int value){
		val = value; 
		left = NULL;
		right = NULL;
	}
}node;

int main(){
	string s;
	map<int, int> in2in;
	int Case = 0;
	stack<node*> st;
	int pos;
	vector<int> data;
	while (getline(cin, s)){
		if (s == "-1") break;
		stringstream ss(s);
		int t;
		while (ss >> t){
			data.push_back(t);
		}
	}
	int position = 0;
	while (position < data.size()){
		pos = 0;
		node* root = new node(data[position]);
		root->pos = 0;
		st.push(root);
		in2in[pos] = data[position];
		position++;
		int length = data.size();
		while (position < length && !st.empty()){
			node *temp = st.top();
			pos = temp->pos;
			while (data[position] != -1){
				temp->left = new node(data[position]);
				temp = temp->left;
				pos--;
				temp->pos = pos;
				if (in2in.find(pos) == in2in.end()) in2in[pos] = data[position];
				else in2in[pos] += data[position];
				position++;
				st.push(temp);
			}
			position++;
			while (position < length&&data[position] == -1){
				st.pop();
				if (st.empty()) break;
				temp = st.top();
				position++;
				pos = temp->pos;
			}
			if (position < length&&data[position] != -1){
				st.pop();
				temp->right = new node(data[position]);
				temp = temp->right;
				pos++;
				temp->pos = pos;
				if (in2in.find(pos) == in2in.end()) in2in[pos] = data[position];
				else in2in[pos] += data[position];
				st.push(temp);
				position++;
			}
		}
		Case++;
		cout << "Case " << Case << ":" << endl;
		for (auto it = in2in.begin(); it != in2in.end();){
			cout << it->second;
			it++;
			if (it != in2in.end()) cout << " ";
		}
		cout << endl << endl;
		in2in.clear();
		position++;
	}
	//system("pause");
	return 0;
}