problem0866

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866. Prime Palindrome

题目

Find the smallest prime palindrome greater than or equal to N.

Recall that anumber is prime if it's only divisors are 1 and itself, and it is greater than 1.

For example, 2,3,5,7,11 and 13 areprimes.

Recall that a number is a palindrome if it reads the same from left to right as it does from right to left.

For example, 12321 is a palindrome.

Example 1:

Input: 6
Output: 7

Example 2:

Input: 8
Output: 11

Example 3:

Input: 13
Output: 101

Note:

1. 1 <= N <= 10^8
2. The answer is guaranteed to exist and be less than 2 * 10^8.

解题思路

见程序注释