Add solution #843

Author: JoshCrozier

README.md

@@ -650,6 +650,7 @@
 840|[Magic Squares In Grid](./0840-magic-squares-in-grid.js)|Medium|
 841|[Keys and Rooms](./0841-keys-and-rooms.js)|Medium|
 842|[Split Array into Fibonacci Sequence](./0842-split-array-into-fibonacci-sequence.js)|Medium|
+843|[Guess the Word](./0843-guess-the-word.js)|Hard|
 844|[Backspace String Compare](./0844-backspace-string-compare.js)|Easy|
 846|[Hand of Straights](./0846-hand-of-straights.js)|Medium|
 867|[Transpose Matrix](./0867-transpose-matrix.js)|Easy|

solutions/0843-guess-the-word.js

@@ -0,0 +1,56 @@
+/**
+ * 843. Guess the Word
+ * https://leetcode.com/problems/guess-the-word/
+ * Difficulty: Hard
+ *
+ * You are given an array of unique strings words where words[i] is six letters long. One word of
+ * words was chosen as a secret word.
+ *
+ * You are also given the helper object Master. You may call Master.guess(word) where word is a
+ * six-letter-long string, and it must be from words. Master.guess(word) returns:
+ * - -1 if word is not from words, or
+ * - an integer representing the number of exact matches (value and position) of your guess to
+ *   the secret word.
+ *
+ * There is a parameter allowedGuesses for each test case where allowedGuesses is the maximum
+ * number of times you can call Master.guess(word).
+ *
+ * For each test case, you should call Master.guess with the secret word without exceeding the
+ * maximum number of allowed guesses. You will get:
+ * - "Either you took too many guesses, or you did not find the secret word." if you called
+ *   Master.guess more than allowedGuesses times or if you did not call Master.guess with the
+ *   secret word, or
+ * - "You guessed the secret word correctly." if you called Master.guess with the secret word
+ *   with the number of calls to Master.guess less than or equal to allowedGuesses.
+ *
+ * The test cases are generated such that you can guess the secret word with a reasonable
+ * strategy (other than using the bruteforce method).
+ */
+
+/**
+ * @param {string[]} words
+ * @param {Master} master
+ * @return {void}
+ */
+var findSecretWord = function(words, master) {
+  for (let attempt = 0; attempt < 30; attempt++) {
+    const randomWord = words[Math.floor(Math.random() * words.length)];
+    const matchCount = master.guess(randomWord);
+
+    if (matchCount === 6) return;
+
+    words = words.filter(word =>
+      matchCount === -1
+        ? countMatches(word, randomWord) === 0
+        : countMatches(word, randomWord) === matchCount
+    );
+  }
+
+  function countMatches(word1, word2) {
+    let matches = 0;
+    for (let i = 0; i < word1.length; i++) {
+      if (word1[i] === word2[i]) matches++;
+    }
+    return matches;
+  }
+};