comefrom: <doocs>0525.Contiguous Array_1.py
code: def findMaxLength( nums: List[int]) -> int:
      s = ans = 0
      mp = {0: -1}
      for i, v in enumerate(nums):
          s += 1 if v == 1 else -1
          if s in mp:
              ans = max(ans, i - mp[s])
          else:
              mp[s] = i
      return ans
masked: def sample_funcname ( var_0 : List [ int ] ) -> int :
      var_5 = var_3 = 0
      var_7 = { 0 : - 1 }
      for var_9 , var_10 in enumerate ( var_0 ) :
          var_5 += 1 if var_10 == 1 else - 1
          if var_5 in var_7 :
              var_3 = max ( var_3 , var_9 - var_7 [ var_5 ] )
          else :
              var_7 [ var_5 ] = var_9
      return var_3
  