Add solution #1178

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,168 LeetCode solutions in JavaScript
+# 1,169 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -916,6 +916,7 @@
 1172|[Dinner Plate Stacks](./solutions/1172-dinner-plate-stacks.js)|Hard|
 1175|[Prime Arrangements](./solutions/1175-prime-arrangements.js)|Easy|
 1177|[Can Make Palindrome from Substring](./solutions/1177-can-make-palindrome-from-substring.js)|Medium|
+1178|[Number of Valid Words for Each Puzzle](./solutions/1178-number-of-valid-words-for-each-puzzle.js)|Hard|
 1189|[Maximum Number of Balloons](./solutions/1189-maximum-number-of-balloons.js)|Easy|
 1200|[Minimum Absolute Difference](./solutions/1200-minimum-absolute-difference.js)|Easy|
 1206|[Design Skiplist](./solutions/1206-design-skiplist.js)|Hard|

solutions/1178-number-of-valid-words-for-each-puzzle.js

@@ -0,0 +1,57 @@
+/**
+ * 1178. Number of Valid Words for Each Puzzle
+ * https://leetcode.com/problems/number-of-valid-words-for-each-puzzle/
+ * Difficulty: Hard
+ *
+ * With respect to a given puzzle string, a word is valid if both the following conditions
+ * are satisfied:
+ * - word contains the first letter of puzzle.
+ * - For each letter in word, that letter is in puzzle.
+ *   - For example, if the puzzle is "abcdefg", then valid words are "faced", "cabbage",
+ *     and "baggage", while
+ *   - invalid words are "beefed" (does not include 'a') and "based" (includes 's' which
+ *     is not in the puzzle).
+ *
+ * Return an array answer, where answer[i] is the number of words in the given word list words
+ * that is valid with respect to the puzzle puzzles[i].
+ */
+
+/**
+ * @param {string[]} words
+ * @param {string[]} puzzles
+ * @return {number[]}
+ */
+var findNumOfValidWords = function(words, puzzles) {
+  const wordMasks = new Map();
+  for (const word of words) {
+    const mask = getBitmask(word);
+    wordMasks.set(mask, (wordMasks.get(mask) || 0) + 1);
+  }
+
+  const result = [];
+  for (const puzzle of puzzles) {
+    const puzzleMask = getBitmask(puzzle);
+    const firstCharBit = 1 << (puzzle.charCodeAt(0) - 97);
+    let count = 0;
+
+    let submask = puzzleMask;
+    do {
+      if (submask & firstCharBit && wordMasks.has(submask)) {
+        count += wordMasks.get(submask);
+      }
+      submask = (submask - 1) & puzzleMask;
+    } while (submask);
+
+    result.push(count);
+  }
+
+  return result;
+
+  function getBitmask(str) {
+    let mask = 0;
+    for (const char of str) {
+      mask |= 1 << (char.charCodeAt(0) - 97);
+    }
+    return mask;
+  }
+};