comefrom: <doocs>2083.Substrings That Begin and End With the Same Letter_1.py
code: def numberOfSubstrings( s: str) -> int:
      counter = [0] * 26
      ans = 0
      for c in s:
          i = ord(c) - ord('a')
          counter[i] += 1
          ans += counter[i]
      return ans
masked: def sample_funcname ( var_0 : str ) -> int :
      var_5 = [ 0 ] * 26
      var_6 = 0
      for var_7 in var_0 :
          var_10 = ord ( var_7 ) - ord ( 'a' )
          var_5 [ var_10 ] += 1
          var_6 += var_5 [ var_10 ]
      return var_6
  