Create 866-prime-palindrome.js

Author: everthis

866-prime-palindrome.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number} N
+ * @return {number}
+ */
+const primePalindrome = function(N) {
+  if(N >= 8 && N <= 11) return 11
+  for(let x = 1; x < 100000; x++) {
+    let s = '' + x, r = s.split('').reverse().join('')
+    let y = +(s + r.slice(1))
+    if(y >= N && isPrime(y)) return y
+  }
+  return -1
+};
+
+function isPrime(x) {
+  if(x < 2 || x % 2 === 0) return x === 2
+  for(let i = 3; i * i <= x; i += 2) {
+    if(x % i === 0) return false
+  }
+  return true
+}