#647

Palindromic Substrings

Medium
StringDP

Given a string `s`, return *the number of **palindromic substrings** in it*.

A string is a **palindrome** when it reads the same backward as forward.

A **substring** is a contiguous sequence of characters within the string.

Examples

Example 1
Input: s = "abc"
Output: 3
Three palindromic strings: "a", "b", "c".
Example 2
Input: s = "aaa"
Output: 6
Six palindromic strings: "a", "a", "a", "aa", "aa", "aaa".

Constraints

  • 1 <= s.length <= 1000
  • s consists of lowercase English letters.
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