目录
[1 移除链表元素](#1 移除链表元素)
[2 链表的中间节点](#2 链表的中间节点)
[3 合并两个有序链表](#3 合并两个有序链表)
[4 反转链表](#4 反转链表)
[5 回文链表](#5 回文链表)
[6 链表中第K个节点](#6 链表中第K个节点)
[7 链表分割](#7 链表分割)
[8 相交链表](#8 相交链表)
[9 环形链表](#9 环形链表)
[10 随机链表的复制](#10 随机链表的复制)
1 移除链表元素
cpp
struct ListNode* removeElements(struct ListNode* head, int val) {
struct ListNode* tail = head;
struct ListNode* prev = head;
while (tail)
{
if (tail->val == val)
{
if (tail == head)
{
head = tail->next;
free(tail);
tail = head;
}
else
{
struct ListNode* next = tail->next;
prev->next = next;
free(tail);
tail = next;
}
}
else
{
prev = tail;
tail = tail->next;
}
}
return head;
}
2 链表的中间节点
cpp
struct ListNode* middleNode(struct ListNode* head) {
struct ListNode* slow = head;
struct ListNode* fast = head;
while (fast && fast->next)
{
fast = fast->next->next;
slow = slow->next;
}
return slow;
}
3 合并两个有序链表
cpp
struct ListNode* mergeTwoLists(struct ListNode* list1, struct ListNode* list2) {
if (list1 == NULL)
{
return list2;
}
if (list2 == NULL)
{
return list1;
}
struct ListNode* head = NULL, * tail = NULL;
//带哨兵位
head = tail = (struct ListNode*)malloc(sizeof(struct ListNode));
//将大的不断尾插到新链表中
while (list1 && list2)
{
if (list1->val < list2->val)
{
tail->next = list1;
list1 = list1->next;
tail = tail->next;
}
else
{
tail->next = list2;
list2 = list2->next;
tail = tail->next;
}
}
if (list1)
{
tail->next = list1;
}
if (list2)
{
tail->next = list2;
}
struct ListNode* newhead = head->next;
free(head);
head = newhead;
return head;
}
4 反转链表
cpp
struct ListNode* reverseList(struct ListNode* head){
struct ListNode* newhead = NULL;
struct ListNode* cur = head;
while(cur)
{
struct ListNode* next = cur->next;
cur->next = newhead;
newhead = cur;
cur = next;
}
return newhead;
}
5 回文链表
cpp
//找中间节点
struct ListNode* middlenode(struct ListNode* head)
{
struct ListNode* slow = head;
struct ListNode* fast = head;
while (fast && fast->next)
{
slow = slow->next;
fast = fast->next->next;
}
return slow;
}
//将中间节点后面的链表进行逆序
struct ListNode* reverseList(struct ListNode* head)
{
struct ListNode* newhead = NULL;
struct ListNode* tail = head;
while (tail)
{
struct ListNode* next = tail->next;
tail->next = newhead;
newhead = tail;
tail = next;
}
return newhead;
}
bool isPalindrome(struct ListNode* head) {
struct ListNode* newhead = middlenode(head);
struct ListNode* node = reverseList(newhead);
//两个链表进行比较
while (head && node)
{
if (head->val != node->val)
{
return false;
}
head = head->next;
node = node->next;
}
return true;
}6 链表中第K个节点
链表中倒数第k个结点_牛客题霸_牛客网 (nowcoder.com)
cpp
struct ListNode* FindKthToTail(struct ListNode* pListHead, int k) {
// write code here
struct ListNode* slow = pListHead;
struct ListNode* fast = pListHead;
while (k)
{
if (fast == NULL)
{
return NULL;
}
fast = fast->next;
k--;
}
while (fast)
{
slow = slow->next;
fast = fast->next;
}
return slow;
}
7 链表分割
面试题 02.04. 分割链表 - 力扣（LeetCode）
cpp
struct ListNode* partition(struct ListNode* head, int x) {
if (head == NULL)
{
return NULL;
}
struct ListNode* ihead, * itail, * ghead, * gtail;
ihead = itail = (struct ListNode*)malloc(sizeof(struct ListNode));
ghead = gtail = (struct ListNode*)malloc(sizeof(struct ListNode));
struct ListNode* cur = head;
itail->next = NULL;
gtail->next = NULL;
while (cur)
{
if (cur->val < x)
{
itail->next = cur;
itail = itail->next;
}
else
{
gtail->next = cur;
gtail = gtail->next;
}
cur = cur->next;
}
itail->next = ghead->next;
gtail->next = NULL;
struct ListNode* newhead = ihead->next;
free(ihead);
free(ghead);
head = newhead;
return head;
}创建两个带头链表 小于x的不断尾插的到链表1 大于x的不断尾插到链表2
8 相交链表
cpp
struct ListNode* getIntersectionNode(struct ListNode* headA, struct ListNode* headB) {
struct ListNode* curA = headA;
struct ListNode* curB = headB;
int lenA = 0, lenB = 0;
while (curA)
{
curA = curA->next;
lenA++;
}
while (curB)
{
curB = curB->next;
lenB++;
}
if (curA != curB)//如果两个链表都为空 就会进来 虽然两个指针都指向空指针 但是不是同一个指针
{
return NULL;
}
int k = abs(lenA - lenB);
if (lenA < lenB)
{
while (k--)
{
headB = headB->next;
}
}
else
{
while (k--)
{
headA = headA->next;
}
}
while (headA != headB)
{
headA = headA->next;
headB = headB->next;
}
return headA;
}
9 环形链表
cpp
bool hasCycle(struct ListNode* head) {
struct ListNode* slow = head;
struct ListNode* fast = head;
while (fast && fast->next)
{
slow = slow->next;
fast = fast->next->next;
if (slow == fast)
{
struct ListNode* meet = slow;
while (meet != head)
{
meet = meet->next;
head = head->next;
}
if (meet == head)
{
return true;
}
}
}
return false;
}
还有一种方法:
cpp
bool GetSameNode(struct ListNode* headA, struct ListNode* headB)
{
struct ListNode* tailA = headA;
struct ListNode* tailB = headB;
int lenA = 1, lenB = 1;
while (tailA)
{
tailA = tailA->next;
lenA++;
}
while (tailB)
{
tailB = tailB->next;
lenB++;
}
if (tailA != tailB)
{
return NULL;
}
int k = abs(lenA - lenB);
if (lenA < lenB)
{
while (k--)
{
headB = headB->next;
}
}
else
{
while (k--)
{
headA = headA->next;
}
}
while (headA != headB)
{
headA = headA->next;
headB = headB->next;
}
return headA == headB;
}
bool hasCycle(struct ListNode* head) {
struct ListNode* slow = head, * fast = head;
while (fast && fast->next)
{
slow = slow->next;
fast = fast->next->next;
if (slow == fast)
{
struct ListNode* meet = slow->next;
slow->next = NULL;
return GetSameNode(meet, head);
}
}
return false;
}10 随机链表的复制
cpp
struct Node* copyRandomList(struct Node* head) {
//复制节点
struct Node* cur = head;
while (cur)
{
struct Node* copy = (struct Node*)malloc(sizeof(struct Node));
struct Node* next = cur->next;
copy->val = cur->val;
cur->next = copy;
copy->next = next;
cur = next;
}
//复制random
cur = head;
while (cur)
{
struct Node* copy = cur->next;
if (cur->random == NULL)
{
copy->random = NULL;
}
else
{
copy->random = cur->random->next;
}
cur = copy->next;
}
//尾插
cur = head;
struct Node* copyhead = NULL, * copytail = NULL;
while (cur)
{
struct Node* copy = cur->next;
struct Node* next = copy->next;
if (copytail == NULL)
{
copyhead = copytail = copy;
}
else
{
copytail->next = copy;
copytail = copytail->next;
}
//恢复原链表
cur->next = next;
//继续走
cur = next;
}
return copyhead;
}
大家可以在力扣上刷一刷这些题目, 非常的实用和干货, 继续加油!