合并两个有序链表自测

Posted 2022-02-06 _BitterSweet

struct ListNode
    int val;
    ListNode* next;
    ListNode(int _val): val(_val),next(nullptr)
;

ListNode* merge(ListNode* l1, ListNode* l2)

    if(l1 == nullptr) return l2;
    if(l2 == nullptr)  return l1;
    
    ListNode* dummy = new ListNode(-1);
    ListNode* cur = dummy;

    while(l1 && l2)
    
        if(l1 -> val <= l2 -> val)
        
            cur -> next = l1;
            l1 = l1 -> next;
        
        else
        
            cur -> next = l2;
            l2 = l2 -> next;
        
        cur = cur -> next;
    
    cur -> next = l1 ? l1 : l2;
    return dummy -> next;


int main(void)

    ListNode* node0 = new ListNode(0);
    ListNode* node1 = new ListNode(1);
    ListNode* node2 = new ListNode(2);
    ListNode* node3 = new ListNode(3);

    ListNode* node4 = new ListNode(1);
    ListNode* node5 = new ListNode(4);

    node0 -> next = node1;
    node1 -> next = node2;
    node2 -> next = node3;
    node3 -> next = nullptr;

    node4 -> next = node5;
    node5 -> next = nullptr;

    
    ListNode* node = merge(node0, node4);
    while(node != nullptr)
    
        cout << node -> val << endl;
        node = node -> next;
    
    return 0;