leetcode Word Pattern
题目连接
https://leetcode.com/problems/word-pattern/
Word Pattern
Description
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:
pattern = “abba”, str = “dog cat cat dog” should return true.
pattern = “abba”, str = “dog cat cat fish” should return false.
pattern = “aaaa”, str = “dog cat cat dog” should return false.
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.
class Solution { public: bool wordPattern(string pattern, string str) { unordered_map<string, char> A; unordered_map<char, string> B; size_t p, i, j = 0, n = pattern.length(); for (i = 0; i < n; i++) { char &ch = pattern[i]; p = str.find(' ', j); string ret = str.substr(j, p - j); if (A.find(ret) == A.end()) A[ret] = ch; else if (A[ret] != ch) return false; if (B.find(ch) == B.end()) B[ch] = ret; else if (B[ch] != ret) return false; j = p + 1; } return i == pattern.size() && p == string::npos; } };
By: GadyPu 博客地址:http://www.cnblogs.com/GadyPu/ 转载请说明