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Leaves - Yitgop #41
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Leaves - Yitgop #41
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{ | ||
// Use IntelliSense to learn about possible attributes. | ||
// Hover to view descriptions of existing attributes. | ||
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387 | ||
"version": "0.2.0", | ||
"configurations": [ | ||
{ | ||
"name": "Listen for rdebug-ide", | ||
"type": "Ruby", | ||
"request": "attach", | ||
"remoteHost": "127.0.0.1", | ||
"remotePort": "1234", | ||
"remoteWorkspaceRoot": "${workspaceRoot}" | ||
} | ||
] | ||
} |
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@@ -19,99 +19,228 @@ def initialize | |||||||
# method to add a new node with the specific data value in the linked list | ||||||||
# insert the new node at the beginning of the linked list | ||||||||
def add_first(value) | ||||||||
raise NotImplementedError | ||||||||
@head = Node.new(value, @head) | ||||||||
end | ||||||||
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# method to find if the linked list contains a node with specified value | ||||||||
# returns true if found, false otherwise | ||||||||
def search(value) | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
checker = @head | ||||||||
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until checker.nil? | ||||||||
return true if checker.data == value | ||||||||
checker = checker.next | ||||||||
end | ||||||||
return false | ||||||||
end | ||||||||
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# method to return the max value in the linked list | ||||||||
# returns the data value and not the node | ||||||||
def find_max | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
max = @head.data | ||||||||
marker = @head.next | ||||||||
until marker.nil? | ||||||||
max = marker.data if marker.data > max | ||||||||
marker = marker.next | ||||||||
end | ||||||||
return max | ||||||||
end | ||||||||
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# method to return the min value in the linked list | ||||||||
# returns the data value and not the node | ||||||||
def find_min | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
min = @head.data | ||||||||
marker = @head.next | ||||||||
until marker.nil? | ||||||||
min = marker.data if marker.data < min | ||||||||
marker = marker.next | ||||||||
end | ||||||||
return min | ||||||||
end | ||||||||
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# method that returns the length of the singly linked list | ||||||||
def length | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
length = 0 | ||||||||
current = @head | ||||||||
until current.nil? | ||||||||
length += 1 | ||||||||
current = current.next | ||||||||
end | ||||||||
return length | ||||||||
end | ||||||||
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# method that returns the value at a given index in the linked list | ||||||||
# index count starts at 0 | ||||||||
# returns nil if there are fewer nodes in the linked list than the index value | ||||||||
def get_at_index(index) | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if index > self.length || index < 0 | ||||||||
curr = @head | ||||||||
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index.times do | ||||||||
curr = curr.next | ||||||||
end | ||||||||
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return curr.data | ||||||||
end | ||||||||
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# method to print all the values in the linked list | ||||||||
def visit | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
curr = @head | ||||||||
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until curr.nil? | ||||||||
p curr.data | ||||||||
curr = curr.next | ||||||||
end | ||||||||
end | ||||||||
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# method to delete the first node found with specified value | ||||||||
def delete(value) | ||||||||
raise NotImplementedError | ||||||||
curr = @head | ||||||||
previous = nil | ||||||||
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return nil if curr.nil? | ||||||||
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until curr.data == value | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This could crash if
Suggested change
Then inside the loop if you find the item to delete, make the deletion and return. |
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if curr.nil? | ||||||||
return nil | ||||||||
else | ||||||||
previous = curr | ||||||||
curr = curr.next | ||||||||
end | ||||||||
end | ||||||||
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if previous == nil | ||||||||
@head = curr.next | ||||||||
else | ||||||||
previous.next = curr.next | ||||||||
end | ||||||||
end | ||||||||
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# method to reverse the singly linked list | ||||||||
# note: the nodes should be moved and not just the values in the nodes | ||||||||
def reverse | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This doesn't seem to work as you never change |
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raise NotImplementedError | ||||||||
return if @head.nil? || @head.next.nil? | ||||||||
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curr = @head | ||||||||
prev = nil | ||||||||
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until curr.nil? | ||||||||
temp = curr.next | ||||||||
curr.next = prev | ||||||||
prev = curr | ||||||||
curr = temp | ||||||||
end | ||||||||
end | ||||||||
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## Advanced Exercises | ||||||||
# returns the value at the middle element in the singly linked list | ||||||||
def find_middle_value | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
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slow = @head | ||||||||
fast = @head.next | ||||||||
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until fast.nil? | ||||||||
slow = slow.next | ||||||||
fast = fast.next.next | ||||||||
end | ||||||||
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return slow.data | ||||||||
end | ||||||||
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# find the nth node from the end and return its value | ||||||||
# assume indexing starts at 0 while counting to n | ||||||||
def find_nth_from_end(n) | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. 👍 |
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raise NotImplementedError | ||||||||
return nil if @head.nil? || self.length < n | ||||||||
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slow = @head | ||||||||
fast = @head | ||||||||
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(n - 1).times do | ||||||||
fast = fast.next | ||||||||
end | ||||||||
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until fast.next.nil? | ||||||||
slow = slow.next | ||||||||
fast = fast.next | ||||||||
end | ||||||||
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return slow.data | ||||||||
end | ||||||||
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# checks if the linked list has a cycle. A cycle exists if any node in the | ||||||||
# linked list links to a node already visited. | ||||||||
# returns true if a cycle is found, false otherwise. | ||||||||
def has_cycle | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This doesn't quite work as the cycle doesn't have to connect the head to the tail, it could be a circle starting toward the end. Like if the last node points to the 2nd to last node. |
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raise NotImplementedError | ||||||||
return false if @head.nil? | ||||||||
marker = @head.next | ||||||||
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until marker.nil? | ||||||||
return true if marker == @head | ||||||||
marker = marker.next | ||||||||
end | ||||||||
return false | ||||||||
end | ||||||||
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# Additional Exercises | ||||||||
# returns the value in the first node | ||||||||
# returns nil if the list is empty | ||||||||
def get_first | ||||||||
raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
return @head.data | ||||||||
end | ||||||||
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# method that inserts a given value as a new last node in the linked list | ||||||||
def add_last(value) | ||||||||
raise NotImplementedError | ||||||||
if @head.nil? | ||||||||
@head = Node.new(value) | ||||||||
end | ||||||||
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curr = @head | ||||||||
self.(length-1).times do | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. This has a typo
Suggested change
|
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curr = curr.next | ||||||||
end | ||||||||
curr.next = Node.new(value) | ||||||||
end | ||||||||
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# method that returns the value of the last node in the linked list | ||||||||
# returns nil if the linked list is empty | ||||||||
def get_last | ||||||||
raise NotImplementedError | ||||||||
return nil if @head.nil? | ||||||||
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curr = @head | ||||||||
until curr.next.nil? | ||||||||
curr = curr.next | ||||||||
end | ||||||||
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return curr.data | ||||||||
end | ||||||||
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# method to insert a new node with specific data value, assuming the linked | ||||||||
# list is sorted in ascending order | ||||||||
def insert_ascending(value) | ||||||||
raise NotImplementedError | ||||||||
@head = Node.new(value) if @head.nil? | ||||||||
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if @head.data > value | ||||||||
temp = @head | ||||||||
@head = Node.new(value) | ||||||||
@head.next = temp | ||||||||
else | ||||||||
curr = @head | ||||||||
until curr.nil? | ||||||||
if value >= curr.data | ||||||||
new = Node.new(value,curr.next.next) | ||||||||
curr.next = new | ||||||||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. You'll want to leave the loop when you add the new node.
Suggested change
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end | ||||||||
curr = curr.next | ||||||||
end | ||||||||
end | ||||||||
end | ||||||||
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# Helper method for tests | ||||||||
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👍