給定一種 pattern(模式) 和一個字串 str ，判斷 str 是否遵循相同的模式。

這裡的遵循指完全匹配，例如， pattern 裡的每個字母和字串 str中的每個非空單詞之間存在著雙向連線的對應模式。

示例1:

輸入: pattern = "abba", str = "dog cat cat dog"
輸出: true

示例 2:

輸入:pattern = "abba", str = "dog cat cat fish"
輸出: false

示例 3:

輸入: pattern = "aaaa", str = "dog cat cat dog"
輸出: false

示例 4:

輸入: pattern = "abba", str = "dog dog dog dog"
輸出: false

建立兩個雜湊表，雙向對應

#include<iostream>
#include<unordered_map>
#include<string>

using namespace std;

class Solution{
public:
	bool wordPattern(string& pattern, string& str)
	{
		vector<string> words=split(str);
		if (pattern.size() != words.size())
			return false;

		unordered_map<char, string> map1;
		unordered_map<string, char> map2;

		for (int i = 0; i < pattern.size(); i++)
		{
			if (map1.count(pattern[i])>0 && map1[pattern[i]] != words[i])
				return false;
			if (map2.count(words[i]) > 0 && map2[words[i]] != pattern[i])
				return false;
			map1[pattern[i]] = words[i];
			map2[words[i]] = pattern[i];
		}
		return true;

	}

	vector<string> split(const string& str)
	{
		vector<string> res;
		string temp;

		for (int i = 0; i <= str.size(); i++)
		{
			if (str[i] == ' ' || str[i] == '\0')
			{
				res.push_back(temp);
				temp.clear();
			}
			else
			{
				temp += str[i];
			}
		}
		return res;
	}


};

int main()
{
	string pattern = "abba";
	string str = "cat dog dog cat";
	bool reslut = Solution().wordPattern(pattern, str);

	if (reslut)
	{
		cout << "true";
	}
	else
	{
		cout << "false";
	}

	system("pause");
	return 0;
}