Suppose we have one N x N grid, each square grid[i][j] represents the elevation at that point (i, j). Now consider it has started raining. At time t, the depth of the water everywhere is t. We can swim from a square to another 4-directionally adjacent square when elevation of both squares individually is at most t. We can swim infinite distance in zero time.We should start from position (0, 0). We have to find the least time until we can reach the bottom right square (N-1, N-1)So if the input is like0123424232221512131515161117181920109876The correct way is colored. So the answer ... Read More

Suppose we have a box that is protected by a password. The password is a sequence of n digits where each digit can be one of the first k digits 0, 1, ..., k-1. So, when we are putting a password, the last n digits entered will automatically be matched against the correct password.So for example, assuming the correct password is "563", if we put "285639", the box will open because the correct password matches the suffix of the entered password. We have to find any password of minimum length that is guaranteed to open the box at some point ... Read More

Suppose we have one N x N grid, this is filled with cherries. Each cell has one of the possible integers as follows −0 − Indicates cell is empty, so we can pass through1 − Indicates cell contains a cherry, that we can pick up and pass through-1 − Indicates the cell is containing a thorn that blocks the wayWe have to collect maximum number of cherries using these few rules −Start from position (0, 0) and end at (N-1, N-1) by moving right or down through valid path cellsAfter reaching the cell (N-1, N-1), returning to (0, 0) by ... Read More

Suppose we have an integer array; we have to find the kth smallest distance among all the pairs. The distance of a pair (A, B) is actually the absolute difference between A and B. So if the input is like [1, 3, 8], then all possible pairs are [1, 3], [3, 8], [1, 8], then when k = 2, the second smallest distance is 5 (8 - 3).To solve this, we will follow these steps −n := size of nums, x := 0for initialize i := 0, when i < n, update (increase i by 1), do −x := maximum ... Read More

Suppose we want a Range Module. This is a module that tracks ranges of numbers. Our task is to design and implement the following interfaces in an efficient manner.addRange(left, right). This will the half-open interval [left, right), tracking every real number in that interval. Now, adding an interval that partially overlaps with currently tracked numbers should add any numbers in the interval that are not already tracked.queryRange(left, right) . This will return true when every real number in the interval [left, right) is currently being tracked.removeRange(left, right), this will stop tracking every real number currently being tracked in the interval ... Read More

Suppose we have a blacklist called B. This is holing unique integers from range [0, N), we have to define a function to return a uniform random integer from range [0, N) which is NOT in B. We will try to make this function more optimized by reducing random(). function call. Suppose the input array is likeTo solve this, we will follow these steps −Define one mapWe will initialize with N and array v.for initalize i := 0, when i < size of v, update (increase i by 1), do −if v[i] < N, then:, m[v[i]] := -1M := N ... Read More

Suppose we have N different types of stickers. In each type of sticker has a lowercase English word on it. We would like to spell out the given target string by cutting individual letters from our collection of stickers and rearranging them. We can use each sticker more than once if needed, and we have infinite quantities of each sticker.We have to find the minimum number of stickers that we need to spell out the target? If the task is impossible, return -1.So if the input is like [“dog”, “sentence”, ”antenna”], and target is “dance”, then the answer will be ... Read More

Suppose we have one array called nums of positive integers, we have to find three non-overlapping subarrays with maximum sum. Here each subarray will be of size k, and we want to maximize the sum of all 3*k entries.We have to find the result as a list of indices representing the starting position of each interval. If there are multiple answers, we will return the lexicographically smallest one.So if the input is like [1, 2, 1, 2, 6, 8, 4, 1] and k = 2, then the result will be [0, 3, 5], so subarrays are [1, 2], [2, 6], ... Read More

Suppose we have a rooted tree. This is a directed graph such that, there is exactly one node (which is the root) for which all other nodes are descendants of this node, and every node has exactly one parent, except for the root node. Root has no parents.In the given input a directed graph that started as a rooted tree with N nodes (All values are unique), with one additional directed edge added. The added edge has two different vertices chosen from 1 to N, and was not an edge that already existed.Graph will be a 2D-array of edges. Each ... Read More

Suppose we know about one Multiplication Table. But could we find out the k-th smallest number quickly from the multiplication table? So if we have to height m and the length n of a m * n Multiplication Table, and one positive integer k, we have need to find the k-th smallest number in this table.So if m = 3 and n = 3 and k is 6, then the output will be 4., this is because the multiplication table is like −1231123224633696th smallest element is 4 as [1, 2, 2, 3, 3, 4, 6, 6, 9]To solve this, we ... Read More