in we carefully examined python' array-based list classand in we demonstrated use of that class in implementing the classic stackqueueand dequeue adts python' list class is highly optimizedand often great choice for storage with that saidthere are some notable disadvantages the length of dynamic array might be longer than the actual number of elements that it stores amortized bounds for operations may be unacceptable in real-time systems insertions and deletions at interior positions of an array are expensive in this we introduce data structure known as linked listwhich provides an alternative to an array-based sequence (such as python listboth array-based sequences and linked lists keep elements in certain orderbut using very different style an array provides the more centralized representationwith one large chunk of memory capable of accommodating references to many elements linked listin contrastrelies on more distributed representation in which lightweight objectknown as nodeis allocated for each element each node maintains reference to its element and one or more references to neighboring nodes in order to collectively represent the linear order of the sequence we will demonstrate trade-off of advantages and disadvantages when contrasting array-based sequences and linked lists elements of linked list cannot be efficiently accessed by numeric index kand we cannot tell just by examining node if it is the secondfifthor twentieth node in the list howeverlinked lists avoid the three disadvantages noted above for array-based sequences singly linked lists singly linked listin its simplest formis collection of nodes that collectively form linear sequence each node stores reference to an object that is an element of the sequenceas well as reference to the next node of the list (see figures and msp element next figure example of node instance that forms part of singly linked list the node' element member references an arbitrary object that is an element of the sequence (the airport code mspin this example)while the next member references the subsequent node of the linked list (or none if there is no further node