Leetcode 83. Remove Duplicates from Sorted List (C語言)

• 題目
  Given a sorted linked list, delete all duplicates such that each element appear only once.
• 範例
  Input: 1->1->2->3->3
  Output: 1->2->3

struct ListNode* deleteDuplicates(struct ListNode* head){
    if(head){
        struct ListNode *current=head,*releasenode;
        while(current->next){
            if(current->val==current->next->val){
                releasenode=current->next;
                current->next=releasenode->next;
                free(releasenode);
            }
            else{
                current=current->next;
            }
        }
    }
    return head;
}

思路:linklist去除多餘元素，因為是sorted list故從頭開始找，若現點與下點值相同，
則將現點指向下下點，free下點。

a          b          c
1    ->    1    ->    3

發現值相同(a點=b點)，將a點指向c點，釋放b點

a          c
1    ->    3