This problem can be solved in very neat codes (yeah, you will see Stefan posting many nice solutions).
The solution in the above link is so nice that I can almost do nothing to improve it instead of using unordered_map -_-
1 class Solution { 2 public: 3 bool wordPattern(string pattern, string str) { 4 unordered_map<char, int> p2i; 5 unordered_map<string, int> w2i; 6 istringstream in(str); 7 int i = 0, n = pattern.length(); 8 for (string word; in >> word; i++) { 9 if (i >= n || p2i[pattern[i]] != w2i[word]) 10 return false; 11 p2i[pattern[i]] = w2i[word] = i + 1; 12 } 13 return i == n; 14 } 15 };
If you wonder why it uses i + 1 instead of simply using i as the values, I mention it at the first comment in the above link :-)
原文：http://www.cnblogs.com/jcliBlogger/p/4857854.html