feat: Add solution for Problem 916 - Word Subsets

- Implemented a solution to find all universal words from a list that meet the character frequency requirements of another list.
- Updated README to include the new problem and solution.
- Incremented daily streak to 67 days.

Author: Zedespook

README.md

@@ -2,7 +2,7 @@
 
 Welcome to my LeetCode solutions repository! This repository contains my solutions to various LeetCode problems, documenting my journey through algorithmic problem-solving and competitive programming. All solutions are implemented in C++.
 
-**Current Daily Streak: 65 days** 🔥
+**Current Daily Streak: 67 days** 🔥
 
 **[Time Travel Tickets](https://support.leetcode.com/hc/en-us/articles/14677342930835-What-Are-Time-Travel-Tickets) Used: 3**
 
@@ -93,6 +93,7 @@ solutions/
 | 2025-01-07 | 1408           | [String Matching in an Array](https://leetcode.com/problems/string-matching-in-an-array/)                                                                   | [Solution](solutions/1408-string-matching-in-an-array/solution.cpp)                                  |
 | 2025-01-08 | 3042           | [Count Prefix and Suffix Pairs I](https://leetcode.com/problems/count-prefix-and-suffix-pairs-i/)                                                           | [Solution](solutions/3042-count-prefix-and-suffix-pairs-i/solution.cpp)                              |
 | 2025-01-09 | 2185           | [Counting Words With a Given Prefix](https://leetcode.com/problems/counting-words-with-a-given-prefix/)                                                     | [Solution](solutions/2185-counting-words-with-a-given-prefix/solution.cpp)                           |
+| 2025-01-10 | 916            | [Word Subsets](https://leetcode.com/problems/word-subsets/)                                                                                                 | [Solution](solutions/916-word-subsets/solution.cpp)                                                  |
 
 ## Personal Goals
 

solutions/916-word-subsets/solution.cpp

@@ -0,0 +1,44 @@
+class Solution {
+private:
+  // Helper function to count character frequencies in a string
+  vector<int> getCharCount(const string &word) {
+    vector<int> count(26, 0);
+    for (char c : word) {
+      count[c - 'a']++;
+    }
+    return count;
+  }
+
+public:
+  vector<string> wordSubsets(vector<string> &words1, vector<string> &words2) {
+    // Get maximum frequency required for each character from words2
+    vector<int> maxFreq(26, 0);
+    for (const string &word : words2) {
+      vector<int> currFreq = getCharCount(word);
+      for (int i = 0; i < 26; i++) {
+        maxFreq[i] = max(maxFreq[i], currFreq[i]);
+      }
+    }
+
+    // Check each word in words1
+    vector<string> result;
+    for (const string &word : words1) {
+      vector<int> freq = getCharCount(word);
+      bool isUniversal = true;
+
+      // Check if word has sufficient frequency for each required character
+      for (int i = 0; i < 26; i++) {
+        if (freq[i] < maxFreq[i]) {
+          isUniversal = false;
+          break;
+        }
+      }
+
+      if (isUniversal) {
+        result.push_back(word);
+      }
+    }
+
+    return result;
+  }
+};