单链表

Insertion

Insert a node at the head(Only 4 steps)

void push(struct Node** head_ref, int new_data){    /* 1. allocate node */    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));    /* 2. put in the data  */    new_node->data  = new_data;    /* 3. Make next of new node as head */    new_node->next = (*head_ref);    /* 4. move the head to point to the new node */    (*head_ref)    = new_node;}

Insert a node at the end

/* Given a reference (pointer to pointer) to the head   of a list and an int, appends a new node at the end  */void append(struct node** head_ref, int new_data){    /* 1. allocate node */    struct node* new_node = (struct node*) malloc(sizeof(struct node));    struct node *last = *head_ref;  /* used in step 5*/    /* 2. put in the data  */    new_node->data  = new_data;    /* 3. This new node is going to be the last node, so make next           of it as NULL*/    new_node->next = NULL;    /* 4. If the Linked List is empty, then make the new node as head */    if (*head_ref == NULL)    {       *head_ref = new_node;       return;    }      /* 5. Else traverse till the last node */    while (last->next != NULL)        last = last->next;    /* 6. Change the next of last node */    last->next = new_node;    return;    }

Deletion

Delete a given key

void deleteNode(struct node **head_ref, int key){    // Store head node    struct node* temp = *head_ref, *prev;    // If head node itself holds the key to be deleted    if (temp != NULL && temp->data == key)    {        *head_ref = temp->next;   // Changed head        free(temp);               // free old head        return;    }    // Search for the key to be deleted, keep track of the    // previous node as we need to change 'prev->next'    while (temp != NULL && temp->data != key)    {        prev = temp;        temp = temp->next;    }    // If key was not present in linked list    if (temp == NULL) return;    // Unlink the node from linked list    prev->next = temp->next;    free(temp);  // Free memory}

逆转链表

static void reverse(struct Node** head_ref){    struct Node* prev   = NULL;    struct Node* current = *head_ref;    struct Node* next;    while (current != NULL)    {        next  = current->next;          current->next = prev;           prev = current;        current = next;    }    *head_ref = prev;}