LeetCode 290. Word Pattern

290. Word Pattern

My Submissions QuestionEditorial Solution

Total Accepted: 33127 Total Submissions: 114634 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 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.

Credits:

Special thanks to @minglotus6 for adding this problem and creating all test cases.

class Solution {
public:
bool wordPattern(string pattern, string str) {
map<char, string> ptos;
map<string, char> stop;
int len = pattern.length();
string *s = new string [len];
int cnt = 0;
for(int i = 0; i < str.length(); i++) {
if(str[i] == ' ')
cnt++;
}
if(cnt != len - 1) {
return false;
}
int t = 0;
for(int i = 0; i < str.length(); i++) {
if(str[i] != ' ') {
s[t] += str[i];
} else {
t++;
}
}
for(int i = 0; i < len; i++) {
if(ptos.find(pattern[i]) != ptos.end() && ptos[pattern[i]] != s[i]
|| stop.find(s[i]) != stop.end() && stop[s[i]] != pattern[i])
return false;
ptos[pattern[i]] = s[i];
stop[s[i]] = pattern[i];
}
return true;
}
};