## Link nodes present in each level of a binary tree in the form of a linked list

Given a binary tree, write an efficient algorithm to link nodes at the same level in the form of a linked list like structure.

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Given a binary tree, write an efficient algorithm to link nodes at the same level in the form of a linked list like structure.

Write an efficient algorithm to find preorder traversal of a binary tree from its inorder and postorder sequence without constructing the tree.

Given an unsorted array of integers whose each element lies in range 0 to n-1 where n is the size of the array, calculate the frequency of all elements present in the array in linear time and using constant space.

Given an array of distinct integers, replace each element of the array by its corresponding rank in the array.

Given a M x N matrix, find all common elements present in every row.

Given an unsorted array of integers containing many duplicates elements, rearrange the given array such that same element appears together and relative order of first occurrence of each element remains unchanged.

Given an array of pairs of integers, find all symmetric pairs i.e. pairs that are mirror of each other. For instance, pairs (x, y) and (y, x) are mirrors of each other.

Write a efficient algorithm to construct the longest palindrome by shuffling or deleting characters from a given string.

Given an array and an integer k, find the count of distinct elements in every sub-array of size k in the array.

Given an array of integers, print all maximum size sub-arrays having all distinct elements in them.

Given an array of integers, find minimum index of a repeating element in linear time and doing just one traversal of the array.

Given a collection of integers, develop an algorithm to find the index of maximum occurring element with equal probability.