title: Count Substrings With Same First And Last Characters
signature: count_substrings_with_same_first_and_last_characters <- function(s) {
source_py: def count_substrings_with_same_first_and_last_characters(s):
      result = 0
      n = len(s)
      for i in range(n):
          for j in range(i, n):
              if (s[i] == s[j]):
                  result = (result + 1)
      return result
source_cpp: int count_substrings_with_same_first_and_last_characters(string s) {
    int result = 0;
    int n = s . length ( );
    for ( int i = 0;
    i < n;
    i ++ ) for ( int j = i;
    j < n;
    j ++ ) if ( s [ i ] == s [ j ] ) result ++;
    return result;
  }