CODEWITHSUNDEEP
pythonglobal
whhcal
whhcal

Reputation: 13

global name 'NAME' is not defined

I am solving this simple question, I'm using recursive DFS to find the minimum path sum.

I wrote a global min_sum to allow me keeping track of the current minimum. Yet, after adding global to my variable inside the dfs function, error message showed.


def get_cheapest_cost(node):

    def dfs(node, route):

        global min_sum

        route.append(node.cost)

        if not node.children:
            min_sum = min(min_sum, sum(route))  

        for c in node.children:
            dfs(c, route)  
        route.pop()

    min_sum = float("inf")    
    dfs(node, [])
    return min_sum



########################################## 
# Use the helper code below to implement #
# and test your function above           #
##########################################

# A node 
class Node:

  # Constructor to create a new node
  def __init__(self, cost):
    self.cost = cost
    self.children = []
    self.parent = None


root = Node(0)
d1_1 = Node(5)
d1_2 = Node(3)
d1_3 = Node(6)
root.children = [d1_1, d1_2, d1_3]

d2_1 = Node(4)
d2_2 = Node(2)
d2_3 = Node(0)
d2_4 = Node(1)
d2_5 = Node(5)

d1_1.children = [d2_1]
d1_2.children = [d2_2, d2_3]
d1_3.children = [d2_4, d2_5]

d3_1 = Node(1)
d3_2 = Node(10)

d2_2.children = [d3_1]
d2_3.children = [d3_2]

d4_1 = Node(1)
d3_1.children = [d4_1]

d4_1 = Node(1)


print(get_cheapest_cost(root))

But it shows: NameError: global name 'min_sum' is not defined

Upvotes: 0

Views: 657

Answers (1)

Dipen Dadhaniya
Dipen Dadhaniya

Reputation: 4630

Please change global min_sum to nonlocal min_sum.

Note: Python 3 introduced the nonlocal keyword that allows us to assign to variables in an outer, but non-global, scope.

Upvotes: 2

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