四种语言刷算法之删除排序链表中的重复元素

力扣83. 删除排序链表中的重复元素

1、C

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */

struct ListNode* deleteDuplicates(struct ListNode* head){
    if(head==NULL||head->next==NULL){
        return head;
    }
    struct ListNode* p = head;
    struct ListNode* q = head->next;
    while(q!=NULL){
        if(p->val==q->val){
            p->next = q->next;
            free(q);
            if(p!=NULL){
                q = p->next;
            }
        }
        else{
            p = q;
            q = q->next;
        }
        
    }
    return head;
}

2、C++

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if(head==nullptr||head->next==nullptr)return head;
        ListNode* p = head;
        ListNode* q = head->next;
        while(q!=nullptr){
            if(p->val==q->val){
                p->next = q->next;
                delete q;
                if(p!=nullptr){
                    q = p->next;
                }
            }
            else{
                p = q;
                q = q->next;
            }
        }
        return head;
    }
};

3、JAVA

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
      if(head==null||head.next==null)return head;
      ListNode p = head;
      ListNode q = head.next;
      while(q!=null){
          if(p.val==q.val){
              p.next = q.next;
              if(p!=null){
                  q = p.next;
              }
          }
          else{
              p = q;
              q = q.next;
          }
      }
      return head;
    }
}

4、Python

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
    def deleteDuplicates(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if head is None or head.next is None:
            return head
        p = head
        q = head.next
        while(q is not None):
            if p.val == q.val:
                p.next = q.next
                if p is not None:
                    q = p.next
            else:
                p = q
                q = p.next
        return head