Get ready for tech Interviews!
This is an easy way to follow/run/test and see even if you code in other language.
1. Cracking the Coding Interviews (CTCI)
> see folders in current dir:
> Beginner
> Intermediate
2. Elements of Programming Interviews (EOPI)
> see folder EOPI in current dir and inside:
> Beginner
> Intermediate
3. External websites, books
> see folder Other in current dir
to do in your free time
———— Beginner: 6.14: Check whether a 9 x 9 grid representing a partially completed Sudoku is valid. Specifically,check that no row, column, and 3 x 3 2D subarray contains duplicates. A O-value in the 2D array indicates that entry is blank; every other entry is in I1,9].6.15: Implement a function which takes a 2D array A and prints A in spiral order.
6.16: Implement a routine that takes a DxD Boolean array A together with an entry (x,y) and flips the color of the region associated with (x,y). See Figure 6.5 for an example of flipping.
6.18: Implement run-length encoding and decoding functions. Assume the string to be encoded consists of letters of the alphabet, with no digits, and the string to be decoded is a valid encoding.6.19: Implement a function for reversing the words in a string. Your function should use 0(1) space.
6.20: Write a function which takes as input a string s, and removes each "b" and replaces each "a" by "dd". Use 0(1) additional storage-assume s is stored in an array that has enough space for the final result.
6.22: Given a cell phone keypad (specified by a mapping M that takes individual digits and returns the corresponding set of characters) and a number se- quence, return all possible character sequences (not just legal words) that correspond to the number sequence.
7.1: Write a function that takes Land F, and returns the merge of L and F. Your code should use 0(1) additional storage-it should reuse the nodes from the lists provided as input. p63.7.3: Write a function that takes a sorted circular singly linked list and a pointer to an arbitrary node in this linked list, and returns the median of the linked list.
7.7: Let v be a node in a singly linked list L. Node v is not the tail: delete it in 0(1) time.
9.9: Given a binary tree, write a function which forms a linked list from the leaves of the binary tree. The leaves should appear in left-to-right order. For example, when applied to the binary tree in Figure 9.1 on Page 73, your function should return (D,E,H,M,N,P).———— Beginner/Intermediate:
6.9: Write a function that takes two strings representing integers, and returns an integer representing their product.6.12: Given a permutation p represented as a vector, return the vector corresponding to the next permutation under lexicographic ordering. If p is the last permutation, return empty vector. For example, if p = (1,0,3,2), your function should return (1,2,0,3).
7.6: Write a function that takes a singly linked list L, and reorders the elements of L so that the new list represents even-odd(L). Try to only use 0(1) additional storage.7.8: Given a singly linked list L and a number k, write a function to remove the k-th last element from L. Your algorithm cannot use more than a few words of storage, regardless of the length of the list. In particular, you cannot assume that it is possible to record the length of the list.
7.11: Let a singly linked list L = [ l1, l2, .., l(n-1), l(n)]. Define zip function ZIP(L) = [l1, l(n-1), l2, l(n-2) … ] Write a function that takes a singly linked list L, and reorders the elements of L to form a new list representing zip(L). Your function should use 0(1) additional storage.
9.6: Design a function that efficientlycomputes the k-thnode appearing in an inorder traversal. Specifically,your function should take as input a binary tree T and an integer k. Each node has a size field, which is the number of nodes in the subtree rooted at that node. What is the time complexity of your function?9.12: Given two nodes in a binary tree T,design an algorithm that computes their LCA (least common ancestor). Assume that each node has a parent pointer. The tree has n nodes and height h. Your algorithm should run in 0(1) space and O(h) time.
10.5: Design an O(n logk) time algorithm that reads a sequence of n elements and for each element, starting from the k-th element, prints the k-th largest element read up to that point. The length of the sequence is not known in advance. Your algorithm cannot use more than O(k) additional storage.
10.6: The input consists of a very long sequence of numbers. Each number is at most k positions away from its correctly sorted position. Design an algorithm that outputs the numbers in the correct order and uses O(k) storage, independent of the number of elements processed.
———— Intermediate:
8.6: Design an algorithm that processes buildings as they are presented to it and tracks the buildings that have a view of the sunset. The number of buildings is not known in advance. Buildings are given in east-to-west order and are specified by their heights. The amount of memory your algorithm uses should depend solely on the number of buildings that have a view; in particular it should not depend on the number of buildings processed. 8.10: Implement a queue API using an array for storing elements. Your API should include a constructor function, which takes as argument the capacity of the queue, enqueue and dequeue functions, a size function, which returns the number of elements stored, and implement dynamic resizing.8.12: How would you implement a queue given two stacks and 0(1) additional storage?Your implementation should be efficient-the time to do a sequence of m combined enqueues and dequeues should be O(m).
11.4: Design analgorithm that takes.an abs-sorted array A and a number k, and returns a pair of indices of elements in A that sum up to k. For example, if the input to your algorithm is the array in Figure 11.2and k = 167,your algorithm should output (3,7). Output (-1, -1) if there is no such pair. (See page 87 in the book)———— Intermediate/Advanced:
7.12: Implement a function which takes as input a pointer to the head of a postings list L, and returns a copy of the postings list. Your function should take O(n) time, where 11 is the length of the postings list and should use 0(1) storage beyond that required for the n nodes in the copy. You can modify the original list, but must restore it to its initial state before returning. 8.11: Implement a queue using two unsigned integer-valued variables. Assume that the only elements pushed into the queue are integers in [0,9]. Your program should work correctly when 0 are the only elements in the queue. What is the maximum number of elements that can be stored in the queue for it to operate correctly?