iOS

How to generate parentheses

[Question]: Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.Example: – n = 2. —   [“(())”, “()()”] Approach: We can solve using backtracking / recursion

How to Remove all occurrence of certain number ?

[Question]: Given an integer array nums and an integer k, remove all occurrences of k in nums in-place. The order of the elements may be changed. Then return the count after removal Approach: We can declare a variable which holds index initial it’s 0 now move elements which are not matched with k

How to rotate linked list with K-th places ?

[Question]: Given the head of a linked list, rotate the list to the right by k places.Example: – Input: head = [1,2,3,4,5], k = 2 Output: [4,5,1,2,3] #Approach Step: 1 Create tail node which moves till endsStep: 2 Create curr the tail node is the (len-k)-th node (1st node is head)Step: 3 Reorder linked list

How to create deep copy of linked list who has random pointer

[Question]: Create a deep copy of the linked list. which consist of exactly n fresh new nodes, where each new node has its value set to the value of its corresponding original node. Both the next and random pointer of the new nodes should point to new nodes in the copied list such that the pointers in the original list and copied list represent …

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