Leetcode 290: 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.

 

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

 

 1 public class Solution {
 2     public bool WordPattern(string pattern, string str) {
 3         var strs = str.Split(' ');
 4         
 5         if (pattern.Length != strs.Length) return false;
 6         
 7         var map = new Dictionary<char, string>();
 8         var reverseMap = new Dictionary<string, char>();
 9         
10         for (int i = 0; i < pattern.Length; i++)
11         {
12             if (map.ContainsKey(pattern[i]))
13             {
14                 if (map[pattern[i]] != strs[i]) return false;
15             }
16             
17             if (reverseMap.ContainsKey(strs[i]))
18             {
19                 if (reverseMap[strs[i]] != pattern[i]) return false;
20             }
21             
22             map[pattern[i]] = strs[i];
23             reverseMap[strs[i]] = pattern[i];
24         }
25         
26         return true;
27     }
28 }

 

posted @ 2017-12-07 05:20  逸朵  阅读(132)  评论(0)    收藏  举报