9.16荣耀笔试第一题

题目：
用哈希表+递归思想解决这道题

#include <unordered_map>
#include <algorithm>
#include <vector>
#include <string>
#include <sstream>
#include <iostream>
using namespace std;

void dfs(unordered_map<string,string>& hstable,string temp,string& ans)
{
	bool flag = false;
	string key = "";
	string ss;
	for (int i = 0; i <temp.size(); i++)
	{
		if (temp[i] != '$' && !flag)
		{
			ans.push_back(temp[i]);
			
		}
		else if (temp[i] == '$')
		{
			flag = true;
			continue;
		}
		if (flag)
		{
			if (temp[i] != '{'&&temp[i] != '}')
			{
				key.push_back(temp[i]);
			}
			else if (temp[i] == '}')
			{
				flag = false;
				ss = hstable.find(key)->second;
				key.clear();
				dfs(hstable,ss,ans);
			}
		}
	}
}
int main()
{
	int n;
	unordered_map<string, string> hstable;
	cin >> n;
	string str;
	string ans;
	for (int i = 0; i < n; i++)
	{
		getline(cin, str);
		if (str == "")
		{
			i--;
			continue;
		}
		stringstream s(str);
		vector<string> vec;
		string temp;
		while (getline(s, temp, '='))
		{
			vec.emplace_back(temp);
		}
		if (i == n - 1)
		{
			ans = vec[1];
		}
		hstable.emplace(vec[0], vec[1]);
	}
	string out;
	dfs(hstable, ans, out);
	cout << out << endl;
	return 0;
}