Create 1394-find-lucky-integer-in-an-array.js

Author: everthis

1394-find-lucky-integer-in-an-array.js

@@ -0,0 +1,18 @@
+/**
+ * @param {number[]} arr
+ * @return {number}
+ */
+const findLucky = function(arr) {
+  const hash = {}
+  for(let e of arr) hash[e] = (hash[e] || 0) + 1
+  let res
+  Object.keys(hash).forEach(k => {
+    if(+k === hash[k]) {
+      if (res == null) res = hash[k]
+      else {
+        if (hash[k] > res) res = hash[k]
+      }
+    } 
+  })
+  return res == null ? -1 : res
+};