Leetcode 290. Word Pattern

290. Word PatternTotal accepted:42115Total submissions:140014 difficulty:easy

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

Here follow means a full match, such that there was a bijection between a letter in and pattern 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:
Assume contains only pattern lowercase letters, and contains lowercase letters separated by str a single space.

Idea: Mapping. Refer to Leetcode 205 for details. The first method of isomorphic strings

Code:

Note the usage of Istringstream, header file <sstream>. This can be used specifically to break down strings that contain spaces .

1 classSolution {2  Public:3     BOOLWordpattern (stringPatternstringstr) {4map<Char,int>P2i;5map<string,int>s2i;6         stringtemp;7         intI=0, n=pattern.size ();8Istringstreaminch(str);9          while(inch>>temp) {Ten             if(i<N) { One                 //there is no corresponding key-value pair in map, 0 is returned A                 if(p2i[pattern[i]]!=S2i[temp]) { -                     return false; -                 } thep2i[pattern[i]]=s2i[temp]=i+1; -             } -i++; -         } +         returni==N; -     } +};

Leetcode 290. Word Pattern