Palindromic Substrings

Problem Description

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.

Example 1:

Input: s = "abc"
Output: 3
Explanation: Three palindromic strings: "a", "b", "c".

Example 2:

Input: s = "aaa"
Output: 6
Explanation: Six palindromic strings: "a", "a", "a", "aa", "aa", "aaa".

Constraints:

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

Solution (Go)

func countSubstrings(s string) int {
	var count int
	for i := 0; i < len(s); i++ {
		var distance int
		for i-distance >= 0 && i+distance < len(s) && s[i-distance] == s[i+distance] {
			count++
			distance++
		}
		distance = 0
		for i-distance >= 0 && i+1+distance < len(s) && s[i-distance] == s[i+1+distance] {
			count++
			distance++
		}
	}
	return count
}