Create 917-reverse-only-letters.js

Author: everthis

917-reverse-only-letters.js

@@ -0,0 +1,37 @@
+/**
+ * @param {string} S
+ * @return {string}
+ */
+const reverseOnlyLetters = function(S) {
+  let start = 0
+  let end = S.length - 1
+  const arr = S.split("")
+  while (start < end) {
+    while (start < end && !chk(S.charCodeAt(start))) {
+      start++
+    }
+    while (start < end && !chk(S.charCodeAt(end))) {
+      end--
+    }
+
+    let tmp = S[end]
+    arr[end] = S[start]
+    arr[start] = tmp
+    start++
+    end--
+  }
+  return arr.join("")
+}
+
+function chk(num) {
+  const aCode = "a".charCodeAt(0)
+  const zCode = "z".charCodeAt(0)
+  const ACode = "A".charCodeAt(0)
+  const ZCode = "Z".charCodeAt(0)
+
+  if ((num >= aCode && num <= zCode) || (num >= ACode && num <= ZCode)) {
+    return true
+  } else {
+    return false
+  }
+}