leetcode-Word Pattern

Given a pattern and a string str, find if str follows the same pattern.

Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.

Examples:

1. pattern = "abba", str = "dog cat cat dog" should return true.

2. pattern = "abba", str = "dog cat cat fish" should return false.

3. pattern = "aaaa", str = "dog cat cat dog" should return false.

4. pattern = "abba", str = "dog dog dog dog" should return false.

四種狀況的測試：

abba/dog cat cat dog/true

abba/dog cat cat fish/false

abba/dog dog dog dog/false 

abba/dog cat cat dog dog/false 

Code

class Solution {
public:
    bool wordPattern(string pattern, string str) {   
        std::map<char, string> smap;
        std::set<string> sset;
        string currentStr;
        char currentChar;
        int len = pattern.length();
        stringstream strs(str);
        bool res=true;
        for(int i=0; i<len; i++)
        { 
            if(strs.eof())
            {
                res=false;
                break;
            }
            strs>>currentStr;
            currentChar = pattern[i];
            if(smap.find(currentChar) != smap.end())
            {
                if(!(smap[currentChar] == currentStr))
                {   
                    res=false;
                    break;
                }
            }
            else
            {
                if(sset.find(currentStr) == sset.end())
                {
                    smap[currentChar] = currentStr;
                    sset.insert(currentStr);
                }
                else
                {
                    res = false;
                    break;
                }
                
            }
        }
        if(!strs.eof())
        {
            res=false;
        }
        return res;
    }
};