用于查找链表长度的 C++ 程序
编写一个函数来计算给定单链表中的节点数。
例如,对于链表 1->3->1->2->1,函数应该返回 5。
迭代解决方案:
1) Initialize count as 0
2) Initialize a node pointer, current = head.
3) Do following while current is not NULL
a) current = current -> next
b) count++;
4) Return count
以下是上述算法的迭代实现,用于查找给定单链表中的节点数。
C++
// Iterative C++ program to find length
// or count of nodes in a linked list
#include
using namespace std;
// Link list node
class Node
{
public:
int data;
Node* next;
};
/* Given a reference (pointer to pointer)
to the head of a list and an int, push
a new node on the front of the list. */
void push(Node** head_ref, int new_data)
{
// Allocate node
Node* new_node =new Node();
// Put in the data
new_node->data = new_data;
// Link the old list off the
// new node
new_node->next = (*head_ref);
// Move the head to point to
// the new node
(*head_ref) = new_node;
}
// Counts no. of nodes in linked list
int getCount(Node* head)
{
// Initialize count
int count = 0;
// Initialize current
Node* current = head;
while (current != NULL)
{
count++;
current = current->next;
}
return count;
}
// Driver code
int main()
{
// Start with the empty list
Node* head = NULL;
// Use push() to construct list
// 1->2->1->3->1
push(&head, 1);
push(&head, 3);
push(&head, 1);
push(&head, 2);
push(&head, 1);
// Check the count function
cout << "count of nodes is " <<
getCount(head);
return 0;
}
// This is code is contributed by rathbhupendra
C++
// Recursive C++ program to find length
// or count of nodes in a linked list
#include
using namespace std;
// Link list node
class Node
{
public:
int data;
Node* next;
};
/* Given a reference (pointer to pointer)
to the head of a list and an int,
push a new node on the front of the list. */
void push(Node** head_ref, int new_data)
{
// Allocate node
Node* new_node = new Node();
// Put in the data
new_node->data = new_data;
// Link the old list off the
// new node
new_node->next = (*head_ref);
// Move the head to point to
// the new node
(*head_ref) = new_node;
}
// Recursively count number of
// nodes in linked list
int getCount(Node* head)
{
// Base Case
if (head == NULL)
{
return 0;
}
// Count this node plus the rest
// of the list
else
{
return 1 + getCount(head->next);
}
}
// Driver code
int main()
{
// Start with the empty list
Node* head = NULL;
// Use push() to construct list
// 1->2->1->3->1
push(&head, 1);
push(&head, 3);
push(&head, 1);
push(&head, 2);
push(&head, 1);
// Check the count function
cout << "Count of nodes is " <<
getCount(head);
return 0;
}
// This is code is contributed by rajsanghavi9
输出:
count of nodes is 5
递归解决方案:
int getCount(head)
1) If head is NULL, return 0.
2) Else return 1 + getCount(head->next)
以下是上述算法的递归实现,用于查找给定单链表中的节点数。
C++
// Recursive C++ program to find length
// or count of nodes in a linked list
#include
using namespace std;
// Link list node
class Node
{
public:
int data;
Node* next;
};
/* Given a reference (pointer to pointer)
to the head of a list and an int,
push a new node on the front of the list. */
void push(Node** head_ref, int new_data)
{
// Allocate node
Node* new_node = new Node();
// Put in the data
new_node->data = new_data;
// Link the old list off the
// new node
new_node->next = (*head_ref);
// Move the head to point to
// the new node
(*head_ref) = new_node;
}
// Recursively count number of
// nodes in linked list
int getCount(Node* head)
{
// Base Case
if (head == NULL)
{
return 0;
}
// Count this node plus the rest
// of the list
else
{
return 1 + getCount(head->next);
}
}
// Driver code
int main()
{
// Start with the empty list
Node* head = NULL;
// Use push() to construct list
// 1->2->1->3->1
push(&head, 1);
push(&head, 3);
push(&head, 1);
push(&head, 2);
push(&head, 1);
// Check the count function
cout << "Count of nodes is " <<
getCount(head);
return 0;
}
// This is code is contributed by rajsanghavi9
输出:
Count of nodes is 5
有关详细信息,请参阅有关查找链表长度(迭代和递归)的完整文章!