Skip to main content

Merge Two Sorted Lists - Leetcode 21 - Python

 21. Merge Two Sorted Lists



You are given the heads of two sorted linked lists list1 and list2.


Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists.


Return the head of the merged linked list.



class Solution:

    def mergeTwoLists(self, l1: Optional[ListNode], l2: Optional[ListNode]) -> Optional[ListNode]:

        d = ListNode()

        p = d

        

        while l1 and l2 :

            if l1.val < l2.val :

                p.next = l1

                l1 = l1.next

            else :

                p.next = l2

                l2 = l2.next

            p = p.next

                

        if l1:

            p.next = l1

        else :

            p.next = l2

        

        return d.next



Explaination :









Labels:

Comments

Post a Comment

Popular posts from this blog

Leetcode 424. Longest Repeating Character Replacement. Python (Sliding Window)

  424 .  Longest Repeating Character Replacement You are given a string  s  and an integer  k . You can choose any character of the string and change it to any other uppercase English character. You can perform this operation at most  k  times. Return  the length of the longest substring containing the same letter you can get after performing the above operations .   Example 1: Input: s = "ABAB", k = 2 Output: 4 Explanation: Replace the two 'A's with two 'B's or vice versa. Example 2: Input: s = "AABABBA", k = 1 Output: 4 Explanation: Replace the one 'A' in the middle with 'B' and form "AABBBBA". The substring "BBBB" has the longest repeating letters, which is 4.   Constraints: 1 <= s.length <= 10 5 s  consists of only uppercase English letters. 0 <= k <= s.length Solution :  class Solution: def characterReplacement(self, s: str, k: int) -> int: hm = {} ans = 0
Post a Comment
Read more

Leetcode 371. Sum of Two Integers. C++ / Java

371 .  Sum of Two Integers   Given two integers  a  and  b , return  the sum of the two integers without using the operators   +   and   - .   Example 1: Input: a = 1, b = 2 Output: 3 Example 2: Input: a = 2, b = 3 Output: 5   Constraints: -1000 <= a, b <= 1000 Solution :  C++ : class Solution { public: int getSum(int a, int b) { if (b==0) return a; int sum = a ^ b; int cr = (unsigned int) (a & b) << 1; return getSum(sum, cr); } }; Java :  class Solution { public int getSum(int a, int b) { while(b != 0){ int tmp = (a & b) << 1; a = a ^ b; b = tmp; } return a; } } Explaination :
Post a Comment
Read more

Leetcode 242. Valid Anagram. Python (3 Ways)

  242 .  Valid Anagram Given two strings  s  and  t , return  true   if   t   is an anagram of   s , and   false   otherwise . An  Anagram  is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.   Example 1: Input: s = "anagram", t = "nagaram" Output: true Example 2: Input: s = "rat", t = "car" Output: false   Constraints: 1 <= s.length, t.length <= 5 * 10 4 s  and  t  consist of lowercase English letters.   Follow up:  What if the inputs contain Unicode characters? How would you adapt your solution to such a case? class Solution: def isAnagram(self, s: str, t: str) -> bool: return sorted(s) == sorted(t) # return Counter(s) == Counter(t) # cs, ct = {}, {} # if len(s) != len(t): # return False # for i in range(len(s)): # cs[s[i]] = 1 + cs.get(s[i], 0) #
Post a Comment
Read more