在C++中填充链表后的额外节点

#include <iostream>

struct ListNode {
    int val;
    ListNode* next;
    ListNode(int x) : val(x), next(nullptr) {}
};

void fillExtraNodes(ListNode* head) {
    ListNode* curr = head;
    while (curr != nullptr) {
        ListNode* extraNode = new ListNode(curr->val);
        extraNode->next = curr->next;
        curr->next = extraNode;
        curr = extraNode->next;
    }
}

int main() {
    // 创建链表
    ListNode* head = new ListNode(1);
    ListNode* node2 = new ListNode(2);
    ListNode* node3 = new ListNode(3);
    head->next = node2;
    node2->next = node3;

    // 填充链表后的额外节点
    fillExtraNodes(head);

    // 打印链表
    ListNode* curr = head;
    while (curr != nullptr) {
        std::cout << curr->val << " ";
        curr = curr->next;
    }

    return 0;
}