# 2083. Substrings That Begin and End With the Same Letter
###### tags: `Leetcode` `Medium` `HashMap`
Link: https://leetcode.com/problems/substrings-that-begin-and-end-with-the-same-letter/description/
## Code

class Solution {
    public long numberOfSubstrings(String s) {
        long ans = 0;
        int[] cnt = new int[26];
        for(int i=0; i<s.length(); i++){
            cnt[s.charAt(i)-'a']++;
            ans += cnt[s.charAt(i)-'a'];
        }
        return ans;
    }
}