LeetCode in Net

290. Word Pattern

Easy

Given a pattern and a string s, find if s 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 s.

Example 1:

Input: pattern = “abba”, s = “dog cat cat dog”

Output: true

Example 2:

Input: pattern = “abba”, s = “dog cat cat fish”

Output: false

Example 3:

Input: pattern = “aaaa”, s = “dog cat cat dog”

Output: false

Example 4:

Input: pattern = “abba”, s = “dog dog dog dog”

Output: false

Constraints:

• 1 <= pattern.length <= 300
• pattern contains only lower-case English letters.
• 1 <= s.length <= 3000
• s contains only lower-case English letters and spaces ' '.
• s does not contain any leading or trailing spaces.
• All the words in s are separated by a single space.

Solution

public class Solution {
    public bool WordPattern(string pattern, string s) {
        Dictionary<char, string> dict = new();
        string[] str = s.Split(" ");
        if (pattern.Length != str.Length) {
            return false;
        }
        for (int i = 0; i < pattern.Length; i++) {
            if (!dict.ContainsKey(pattern[i]) && !dict.ContainsValue(str[i])) {
                dict.Add(pattern[i], str[i]);
            }
            if (!dict.ContainsKey(pattern[i]) || !str[i].Equals(dict[pattern[i]])) {
                return false;
            }
        }
        return true;
    }
}

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