wordBreak solution

Author: Moonjonghoo

word-break/moonjonghoo.js

@@ -0,0 +1,31 @@
+/**
+ * @param {string} s
+ * @param {string[]} wordDict
+ * @return {boolean}
+ */
+var wordBreak = function (s, wordDict) {
+  const memo = new Map(); // 실패/성공 여부 기억
+  const wordSet = new Set(wordDict); // lookup 최적화
+
+  function canBreak(sub) {
+    if (sub === "") return true;
+
+    if (memo.has(sub)) return memo.get(sub);
+
+    for (let i = 1; i <= sub.length; i++) {
+      const prefix = sub.slice(0, i);
+      if (wordSet.has(prefix)) {
+        const suffix = sub.slice(i);
+        if (canBreak(suffix)) {
+          memo.set(sub, true);
+          return true;
+        }
+      }
+    }
+
+    memo.set(sub, false); // 실패한 경우도 기억
+    return false;
+  }
+
+  return canBreak(s);
+};