comefrom: <doocs>0724.Find Pivot Index_1.py
code: def pivotIndex( nums: List[int]) -> int:
      s, presum = sum(nums), 0
      for i, v in enumerate(nums):
          if (presum << 1) == s - v:
              return i
          presum += v
      return -1
masked: def sample_funcname ( var_0 : List [ int ] ) -> int :
      var_4 , var_6 = sum ( var_0 ) , 0
      for var_8 , var_9 in enumerate ( var_0 ) :
          if ( var_6 << 1 ) == var_4 - var_9 :
              return var_8
          var_6 += var_9
      return - 1
  