擅长:python、mysql、java
<p>如果您有输入错误,请参阅addBefore方法中的#TODO:</p>
<pre><code> def addBefore(self, valueToFind, newNode):
currentNode = self.headval
previousNode = None
while currentNode is not None:
# We found the element we will insert before
if (currentNode.dataval == valueToFind):
# Set our new node's next value to the current element
newNode.nextval = currentNode
# If we are inserting at the head position
if (previousNode is None):
self.headval = newNode
else:
# Change previous node's next to our new node
previousNode.nexval = newNode #TODO: Fix Typo: nexval
return 0
# Update loop variables
previousNode = currentNode
currentNode = currentNode.nextval
return -1
</code></pre>