[LeetCode] 83. Remove Duplicates from Sorted List

轉自LeetCode

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

<Solution>

這題不困難，注意 link list 的操作就好

解題想法如下

• 用兩個指針，prv 和 curr 來檢查數值是否重複

• 重複的話，就把 curr 往後移

• 不重複的話，就把 prv->next 指到 curr

code 如下
c++

	/**
	* Definition for singly-linked list.
	* struct ListNode {
	* int val;
	* ListNode *next;
	* ListNode(int x) : val(x), next(NULL) {}
	* };
	*/
	class Solution {
	public:
	ListNode* deleteDuplicates(ListNode* head) {
	if(!head) {
	return NULL;
	}
	ListNode *prv = head;
	ListNode *curr = head->next;
	while(curr) {
	if(curr->val > prv->val) {
	prv->next = curr;
	prv = curr;
	}
	curr = curr->next;
	}
	prv->next = curr;
	return head;
	}
	};

view raw removeDuplicatesFromSortedLinkList.cpp hosted with ❤ by GitHub

kotlin

	/**
	* Example:
	* var li = ListNode(5)
	* var v = li.`val`
	* Definition for singly-linked list.
	* class ListNode(var `val`: Int) {
	* var next: ListNode? = null
	* }
	*/
	class Solution {
	fun deleteDuplicates(head: ListNode?): ListNode? {
	return if (head == null || head.next == null) {
	head
	} else {
	var prv = head
	var cur = head.next
	while(cur != null) {
	if (cur!!.`val` > prv!!.`val`) {
	prv.next = cur
	prv = cur
	}
	cur = cur.next
	}
	prv!!.next = cur
	return head
	}
	}
	}

view raw remove_duplicates_from_sorted_list.kt hosted with ❤ by GitHub