2022-03-09 Daily-Challenge

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In: DailyChallenge

Today I have done leetcode's March LeetCoding Challenge with cpp.

March LeetCoding Challenge 9

Description

Remove Duplicates from Sorted List II

Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well.

Example 1:

img

Input: head = [1,2,3,3,4,4,5]
Output: [1,2,5]

Example 2:

img

Input: head = [1,1,1,2,3]
Output: [2,3]

Constraints:

  • The number of nodes in the list is in the range [0, 300].
  • -100 <= Node.val <= 100
  • The list is guaranteed to be sorted in ascending order.

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  ListNode* deleteDuplicates(ListNode* head) {
    ListNode *newHead = new ListNode();
    ListNode *newCur = newHead;
    while(head) {
      if(head->next && head->val == head->next->val) {
        int val = head->val;
        while(head && head->val == val) head = head->next;
        continue;
      }
      newCur->next = head;
      newCur = newCur->next;
      head = head->next;
    }
    newCur->next = nullptr;
    return newHead->next;
  }
};

// Accepted
// 166/166 cases passed (19 ms)
// Your runtime beats 16.25 % of cpp submissions
// Your memory usage beats 20.51 % of cpp submissions (11.2 MB)
Algorithm