Update 906-super-palindromes.js

Author: everthis

906-super-palindromes.js

@@ -153,3 +153,48 @@ const isPalindrome = function (nr) {
     return true;
   }
 };
+
+// another
+
+/**
+ * @param {string} left
+ * @param {string} right
+ * @return {number}
+ */
+const superpalindromesInRange = function (left, right) {
+  let ans = 9 >= left && 9 <= right ? 1 : 0
+
+  const isPal = (str) => {
+    for (let i = 0, j = str.length - 1; i < j; i++, j--)
+      if (str.charAt(i) !== str.charAt(j)) return false
+    return true
+  }
+
+  for (let dig = 1; dig < 10; dig++) {
+    let isOdd = dig % 2 && dig !== 1,
+      innerLen = (dig >> 1) - 1,
+      innerLim = Math.max(1, 2 ** innerLen),
+      midPos = dig >> 1,
+      midLim = isOdd ? 3 : 1
+    for (let edge = 1; edge < 3; edge++) {
+      let pal = new Uint8Array(dig)
+      ;(pal[0] = edge), (pal[dig - 1] = edge)
+      if (edge === 2) (innerLim = 1), (midLim = Math.min(midLim, 2))
+      for (let inner = 0; inner < innerLim; inner++) {
+        if (inner > 0) {
+          let innerStr = inner.toString(2).padStart(innerLen, '0')
+          for (let i = 0; i < innerLen; i++)
+            (pal[1 + i] = innerStr[i]), (pal[dig - 2 - i] = innerStr[i])
+        }
+        for (let mid = 0; mid < midLim; mid++) {
+          if (isOdd) pal[midPos] = mid
+          let palin = ~~pal.join(''),
+            square = BigInt(palin) * BigInt(palin)
+          if (square > right) return ans
+          if (square >= left && isPal(square.toString())) ans++
+        }
+      }
+    }
+  }
+  return ans
+}