[leet] word ladder 다시 품 (hard)

Author: hyeonbinHur

허현빈/5주차/260129-1.js

@@ -37,3 +37,4 @@ var ladderLength = function (beginWord, endWord, wordList) {
   return ans;
 };
 //시간복잡도 터짐 실패
+//20분정도 푼듯

허현빈/5주차/260129-2.js

@@ -0,0 +1,51 @@
+/**
+ * @param {string} beginWord
+ * @param {string} endWord
+ * @param {string[]} wordList
+ * @return {number}
+ */
+var ladderLength = function (beginWord, endWord, wordList) {
+  const matches = (word1, word2) => {
+    let count = 0;
+    for (let j = 0; j < word1.length; j++) {
+      if (word1[j] !== word2[j]) {
+        count++;
+        if (count >= 2) return false;
+      }
+    }
+    return count === 1;
+  };
+
+  let finalAns = Infinity;
+
+  const bfs = (startWord, startIdx) => {
+    const q = [[startWord, 2]];
+    const visit = Array.from({ length: wordList.length }).fill(false);
+    visit[startIdx] = true;
+
+    while (q.length > 0) {
+      const [cur, ladderCount] = q.shift();
+
+      if (cur === endWord) {
+        finalAns = Math.min(finalAns, ladderCount);
+      }
+
+      for (let i = 0; i < wordList.length; i++) {
+        if (!visit[i] && matches(cur, wordList[i])) {
+          visit[i] = true;
+          q.push([wordList[i], ladderCount + 1]);
+        }
+      }
+    }
+  };
+
+  for (let i = 0; i < wordList.length; i++) {
+    if (matches(beginWord, wordList[i])) {
+      bfs(wordList[i], i);
+    }
+  }
+
+  return finalAns === Infinity ? 0 : finalAns;
+};
+// bfs로 다시품 정답
+// 10분젇도 더 쓴듯