在不交换数据的情况下对C++中的双向链表进行排序,可以通过修改节点的指针来实现。以下是一种可能的实现方法:
下面是一个示例代码:
#include <iostream>
struct Node {
int data;
Node* prev;
Node* next;
};
Node* getMiddle(Node* start, Node* end) {
Node* slow = start;
Node* fast = start;
while (fast != end && fast->next != end) {
slow = slow->next;
fast = fast->next->next;
}
return slow;
}
Node* merge(Node* left, Node* right) {
Node dummy;
Node* tail = &dummy;
while (left && right) {
if (left->data <= right->data) {
tail->next = left;
left->prev = tail;
left = left->next;
} else {
tail->next = right;
right->prev = tail;
right = right->next;
}
tail = tail->next;
}
tail->next = left ? left : right;
tail->next->prev = tail;
return dummy.next;
}
Node* mergeSort(Node* start, Node* end) {
if (start == end || start->next == end) {
return start;
}
Node* middle = getMiddle(start, end);
Node* right = mergeSort(middle, end);
Node* left = mergeSort(start, middle);
return merge(left, right);
}
Node* sortLinkedList(Node* head) {
return mergeSort(head, nullptr);
}
void printLinkedList(Node* head) {
Node* current = head;
while (current) {
std::cout << current->data << " ";
current = current->next;
}
std::cout << std::endl;
}
int main() {
// 创建一个双向链表
Node* head = new Node{5, nullptr, nullptr};
Node* node1 = new Node{3, nullptr, nullptr};
Node* node2 = new Node{8, nullptr, nullptr};
Node* node3 = new Node{1, nullptr, nullptr};
Node* node4 = new Node{6, nullptr, nullptr};
head->next = node1;
node1->prev = head;
node1->next = node2;
node2->prev = node1;
node2->next = node3;
node3->prev = node2;
node3->next = node4;
node4->prev = node3;
std::cout << "Before sorting: ";
printLinkedList(head);
head = sortLinkedList(head);
std::cout << "After sorting: ";
printLinkedList(head);
// 释放链表内存
Node* current = head;
while (current) {
Node* temp = current;
current = current->next;
delete temp;
}
return 0;
}
这段代码实现了对双向链表的排序,通过递归地将链表分为两部分并排序,然后再合并排序后的两部分。在合并过程中,通过比较节点的值来确定节点的顺序,并调整节点的指针。最后输出排序后的链表。
请注意,这只是一种可能的实现方法,实际应用中可能会根据具体需求进行调整。
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