112 lines
2.1 KiB
C
112 lines
2.1 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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typedef struct node
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{
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char Character;
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struct node *Next;
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struct node *Prev;
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}node;
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// TODO: change all the function to use a dlinked list
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node *alloc_node(char c, node *Next, node *Prev)
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{
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node *NewNode = malloc(sizeof(node));
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NewNode->Character = c;
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NewNode->Next = Next;
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return NewNode;
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}
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// TIP: In the next 2 function you probably need to check for null-pointers
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// NOTE: adds an element to the beginning
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void list_add(node **Head, char c)
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{
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node *NewNode = alloc_node(c, *Head, 0);
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*Head = NewNode;
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}
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// NOTE: inserts after a specific node
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void list_insert_after(node *Node, char c)
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{
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node *NewNode = alloc_node(c, Node->Next, 0);
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Node->Next = NewNode;
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}
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// NOTE: get's a node with the specified character
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node *list_get(node **Head, char c)
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{
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node *Result;
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for(node *Iter = *Head; Iter; Iter = Iter->Next)
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{
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if(Iter->Character == c)
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{
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Result = Iter;
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break;
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}
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}
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return Result;
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}
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// NOTE: removes a specific node from the list
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void list_remove(node **Head, node *Node)
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{
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// NOTE: this should get simpler
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// Find prev node
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node *Prev = 0;
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for(node *Iter = *Head; Iter; Iter = Iter->Next)
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{
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if(Iter == Node)
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break;
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Prev = Iter;
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}
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if(Prev)
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Prev->Next = Node->Next;
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free(Node);
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}
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// NOTE: frees the whole list
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void list_free(node **Head)
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{
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for(node *Iter = *Head; Iter; )
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{
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node *ToFree = Iter;
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Iter = Iter->Next;
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free(ToFree);
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}
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}
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int main(int argc, char **argv)
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{
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node *Head = 0;
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list_add(&Head, 'c');
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list_add(&Head, 'y');
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list_add(&Head, 'b');
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node *ToBeRemoved = list_get(&Head, 'y');
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list_remove(&Head, ToBeRemoved);
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list_add(&Head, 'a');
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node *InsertAfter = list_get(&Head, 'c');
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list_insert_after(InsertAfter, 'd');
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// NOTE: prints out the whole list
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for(node *Iter = Head; Iter; Iter = Iter->Next)
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{
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printf("%c ", Iter->Character);
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}
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printf("\n");
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// NOTE: prints out the previous Node of B, B and the next one
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node *B = list_get(&Head, 'b');
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if(B)
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{
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printf("%s %c %s\n",B->Prev? B->Prev: "Null", B->Character, B->Next? B->Next: "Null");
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}
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list_free(&Head);
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}
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