Word Pattern

题目描述:

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.

Notes:
You may assume pattern contains only lowercase letters, and str contains lowercase letters separated by a single space.

题目思路:

用两个哈希表，将两个字符串的对应位置给予相同的映射，如果已有映射不相同，则返回false

题目代码:

class Solution {
public:bool wordPattern(string pattern, string str) {istringstream in(str);map<string,int>table1;map<char, int>table2;int i = 0, n = pattern.length();for(string word; in >> word; i++){if(table2[pattern[i]] != table1[word] || i==n){return false;}else{table1[word] = table2[pattern[i]] = i+1;}}return i==n;}
};