Suppose there is a ball in a maze with empty spaces and walls. Now the ball can go through empty paths by rolling any direction like up, down, left or right, but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction.We have to start position of ball, the destination and the maze, we have to check whether the ball could stop at the destination. The maze is represented by one 2D array. Here 1 indicates the wall and 0 indicates the empty space. The borders of the maze are all walls. ... Read More

Suppose we have a binary array; we have to find the maximum number of consecutive 1s in this array if we can flip at most one 0.So, if the input is like [1, 0, 1, 1, 0], then the output will be 4 because if we flip the first zero will get the maximum number of consecutive 1s. After flipping, the maximum number of consecutive 1s is 4.To solve this, we will follow these steps −ret := 1, n := size of numsif not n is non-zero, then −return 0j := 0, zero := 0for initialize i := 0, when ... Read More

Suppose we have a secret signature consisting of character 'D' and 'I'. 'D' denotes the decreasing relationship between two numbers, 'I' denotes increasing relationship between two numbers. And the secret signature was constructed by a special integer array, which contains uniquely all the different number from 1 to n.For example, the secret signature "DI" can be constructed from an array like [2, 1, 3] or [3, 1, 2], but not be constructed using array like [3, 2, 4] or [2, 1, 3, 4], which are both illegal constructing special string that can't represent the "DI" secret signature.Now we have to ... Read More

Suppose we have to check whether the original sequence org can be uniquely reconstructed from the sequences in seqs. The original sequence is a permutation of the integers from 1 to n, and n in range 1 ≤ n ≤ 10^4. Here the reconstruction means making a shortest common supersequence of the sequences in seqs. We have to check whether there is only one sequence that can be reconstructed from seqs and it is the original sequence.So, if the input is like org = [1, 2, 3], seqs = [[1, 2], [1, 3]], then the output will be false, because ... Read More

Suppose we want to design a Phone Directory which supports the following operations −get − This will provide a number that is not assigned to anyone.check − This will check whether a number is available or not.release − This will recycle or release a number.Using the initializer, we can initialize n numbers at firstTo solve this, we will follow these steps −Define one set sDefine one queue availableThe initializer will take maxNumbers.N := maxNumbersfor initialize i := 0, when i < N, update (increase i by 1), do −insert i into availableDefine a function get()if size of available is same ... Read More

Suppose we have an array of size n and that is initialized with 0's and we also have a value k, we will perform k update operations. Each operation will be represented as triplet: [startIndex, endIndex, inc] which increments each element of subarray A[startIndex ... endIndex] (startIndex and endIndex inclusive) with inc. We have to find the modified array after all k operations were executed.So, if the input is like length = 5, updates = [[1, 3, 2], [2, 4, 3], [0, 2, -2]], then the output will be [- 2, 0, 3, 5, 3]To solve this, we will follow ... Read More

Suppose we have a non-negative integer represented as non-empty a singly linked list of digits, now we have to plus one to the integer. We may assume the integer do not contain any leading zero, except the number 0 itself. In the linked list the most significant digit is at the head of the list.So, if the input is like [1, 2, 3], then the output will be [1, 2, 4]To solve this, we will follow these steps −if head is null, then −return headcurr = headreq = NULLwhile curr is non-zero, do −if val of curr is not equal ... Read More

Suppose we have a binary tree. We will collect and remove all leaves and repeat until the tree is empty.So, if the input is likethen the output will be [[4, 5, 3], [2], [1]]To solve this, we will follow these steps −Define one map szDefine one 2D array retDefine a function dfs(), this will take node, if node is null, then −sz[val of node] := 1 + maximum of dfs(left of node) and dfs(right of node)if size of ret < sz[val of node], then −Define an array tempinsert temp at the end of retinsert val of node at the end ... Read More

Given a nested list of integers, return the sum of all integers in the list weighted by their depth. Each element is either an integer, or a list -- whose elements may also be integers or other lists. Different from the previous question where weight is increasing from root to leaf, now the weight is defined from bottom up. i.e., the leaf level integers have weight 1, and the root level integers have the largest weight.So, if the input is like [[1, 1], 2, [1, 1]], then the output will be 8, as four 1's at depth 1, one 2 ... Read More

Suppose we want to design a hit counter which counts the number of hits received in the past 5 minutes. There will be a function and that accepts a timestamp parameter in the second unit and we may assume that calls are being made to the system in chronological order (so, the timestamp is monotonically increasing). We also assume that the earliest timestamp starts at 1.It is possible that several hits arrive roughly at the same time.So we will call the hit() function to hit and getHits() function to get the count of hits.To solve this, we will follow these ... Read More