906

Author: ProHiryu

Palindrome/906.md

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+## Super Palindromes
+
+#### Description
+
+[link](https://leetcode.com/problems/super-palindromes/)
+
+---
+
+#### Solution
+
+- See Code
+
+---
+
+#### Code
+
+> O(10^5)
+
+```python
+class Solution:
+    def superpalindromesInRange(self, L: str, R: str) -> int:
+        L, R = int(L), int(R)
+        # 确定所有能构建回文的数字的范围，然后判断即可
+        left = int(math.floor(math.sqrt(L)))
+        right = int(math.ceil(math.sqrt(R)))
+        
+        n1, n2 = len(str(left)), len(str(right))
+        
+        n1 = n1//2 if n1%2==0 else n1//2+1
+        n2 = n2//2 if n2%2==0 else n2//2+1
+        
+        start = int('1' + '0'*(n1-1))
+        end = int('9'*n2)+1
+        
+        ans = 0
+        for i in range(start, end):
+            x = str(i)
+            num1 = int(x + x[::-1])
+            num2 = int(x + x[:-1][::-1])
+            for num in [num1, num2]:
+                cand = num*num
+                if cand >= L and cand <= R and str(cand) == str(cand)[::-1]:
+                    ans += 1
+        return ans
+```