1.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:
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.
2.分析
3.代码
class Solution {
public:
bool wordPattern(string pattern, string str) {
map<char, int> p2i;
map<string, int> w2i;
istringstream iss(str);
int i = 0, n = pattern.size();
for (string word; iss >> word; i++) {
if (i == n || p2i[pattern[i]] != w2i[word]) {
return false;
}
p2i[pattern[i]] = w2i[word] = i + 1;
}
return i == n;
}
};
