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Data Structure HKOI training 2009 3/4/2010 So Pak Yeung
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What is data structure? a particular way of storing and organizing data in a computer so that it can be used efficiently. From wikipedia
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Outline Stack Stack Queue Queue Linked list Linked list
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Stack Last In First Out (LIFO) Last In First Out (LIFO) Operations: Operations: PushPush PopPop
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Stack - Push Put an element on the top of the stack Put an element on the top of the stack if (top==MAX_SIZE) //stack is full output error: stack overflow output error: stack overflow else stack[top++] = data; stack[top++] = data;
![Stack - Push Put an element on the top of the stack Put an element on the top of the stack if (top==MAX_SIZE) //stack is full output error: stack overflow output error: stack overflow else stack[top++] = data; stack[top++] = data;](http://images.slideplayer.com./6/1607811/slides/slide_5.jpg "Stack - Push Put an element on the top of the stack Put an element on the top of the stack if (top==MAX_SIZE) //stack is full output error: stack overflow output error: stack overflow else stack[top++] = data; stack[top++] = data;")
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Stack - Pop Remove the element on the top of the stack Remove the element on the top of the stack if (top==0) //the stack is empty output Error: stack underflow output Error: stack underflow else{ // tmp = stack[--top]; --top;}
![Stack - Pop Remove the element on the top of the stack Remove the element on the top of the stack if (top==0) //the stack is empty output Error: stack underflow output Error: stack underflow else{ // tmp = stack[--top]; --top;}](http://images.slideplayer.com./6/1607811/slides/slide_6.jpg "Stack - Pop Remove the element on the top of the stack Remove the element on the top of the stack if (top==0) //the stack is empty output Error: stack underflow output Error: stack underflow else{ // tmp = stack[--top]; --top;}")
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Queue First In First Out (FIFO) First In First Out (FIFO) Operations: Operations: EnqueueEnqueue DequeueDequeue
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Queue - Enqueue Add an element at the end of the queue Add an element at the end of the queue if (e == MAX) output Error output Error else queue[e++] = data;
![Queue - Enqueue Add an element at the end of the queue Add an element at the end of the queue if (e == MAX) output Error output Error else queue[e++] = data;](http://images.slideplayer.com./6/1607811/slides/slide_8.jpg "Queue - Enqueue Add an element at the end of the queue Add an element at the end of the queue if (e == MAX) output Error output Error else queue[e++] = data;")
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Queue: Dequeue Remove the element at the front of the queue Remove the element at the front of the queue if (f==e) //empty queue output error output error else{ // tmp = queue[f]; ++f;}
![Queue: Dequeue Remove the element at the front of the queue Remove the element at the front of the queue if (f==e) //empty queue output error output error else{ // tmp = queue[f]; ++f;}](http://images.slideplayer.com./6/1607811/slides/slide_9.jpg "Queue: Dequeue Remove the element at the front of the queue Remove the element at the front of the queue if (f==e) //empty queue output error output error else{ // tmp = queue[f]; ++f;}")
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Queue Not efficient in terms of memory Not efficient in terms of memory Improvement: Improvement: Using linked list to implementUsing linked list to implement Circular QueueCircular Queue
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Linked List Data + Pointers Data + Pointers Operations: Operations: InsertionInsertion DeletionDeletion
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Linked List data1 data2data3data4 null head
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Linked List - Insertion Assume we add a node after node 2 data1 data2data3data4 null head
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Linked List - Insertion data1 data2data3data4 null new data head
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Linked List - Insertion data1 data2data3data4 null new data head
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Linked List - Insertion data1 data2data3data4 null new data head
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Linked List - Insertion node* tmp = new node; tmp->data = new_data; tmp->next = target->next; target->next = tmp;
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Linked List - Deletion Assume we delete node 3 data1 data2data3data4 null head
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Linked List - Deletion data1 data2data3data4 null tmp head
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Linked List - Deletion data1 data2data3data4 null tmp head
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Linked List - Deletion data1 data2data4 null head
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Linked List - Deletion node* tmp = target->next; target->next = tmp->next; delete tmp;
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Linked List It is so troublesome when we try to delete the first node / insert before the first node It is so troublesome when we try to delete the first node / insert before the first node Dummy node Dummy node Doubly Linked List Doubly Linked List
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Linked List data1 data2data3data4 null head
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Types of Linked List Singly-Linked List Singly-Linked List Doubly-Linked List Doubly-Linked List Circularly-Linked List Circularly-Linked List
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Questions?
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