From f199f1fc3a2c6f8d12f289a328dd7c040e89ad31 Mon Sep 17 00:00:00 2001
From: BangDori <qudwns8865@naver.com>
Date: Thu, 9 Jan 2025 21:38:07 +0900
Subject: [PATCH] [Leetcode - Medium] Decode Ways

---
 bangdori/Decode Ways.js | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 bangdori/Decode Ways.js

diff --git a/bangdori/Decode Ways.js b/bangdori/Decode Ways.js
new file mode 100644
index 0000000..6ae8214
--- /dev/null
+++ b/bangdori/Decode Ways.js	
@@ -0,0 +1,26 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+var numDecodings = function (s) {
+  if (s[0] === "0") return 0;
+
+  const sLen = s.length;
+  const dp = new Array(sLen + 1).fill(0);
+  dp[0] = dp[1] = 1;
+
+  for (let i = 2; i <= sLen; i++) {
+    const oneDigit = parseInt(s[i - 1]);
+    const twoDigit = parseInt(s.substring(i - 2, i));
+
+    if (1 <= oneDigit && oneDigit <= 9) {
+      dp[i] += dp[i - 1];
+    }
+
+    if (10 <= twoDigit && twoDigit <= 26) {
+      dp[i] += dp[i - 2];
+    }
+  }
+
+  return dp[sLen];
+};