Suppose we have a list of strings, we can concatenate these strings together into a loop, where for each string we can choose to reverse it or not. Among all of the possible loops, we need to find the lexicographically largest string after cutting the loop, which will make the looped string into a regular one. Specifically, to find the lexicographically largest string, we need to experience two phases −Concatenate all the strings into one loop, where we can reverse some strings or not and connect them in the same order as given.Cut and make one cutting point in any ... Read More

Suppose we have a binary tree; we have to find the length of the Longest Consecutive Path in that Binary Tree. Here the path can be either increasing or decreasing. So as an example [1, 2, 3, 4] and [4, 3, 2, 1] are both considered as a valid path, but the path [1, 2, 4, 3] is not a valid one.Otherwise, the path can be in the child-Parent-child sequence, where not necessarily be parent-child order.So, if the input is likethen the output will be 3 as the longest consecutive path will be like [1, 2, 3] or [3, 2, ... Read More

Suppose we have an array with n integers, we have to find if there are triplets (i, j, k) which follows these conditions −0 < i, i + 1 < j, j + 1 < k < n - 1Sum of subarrays (0, i - 1), (i + 1, j - 1), (j + 1, k - 1) and (k + 1, n - 1) will be same.The subarray (L, R) is a slice of the original array starting from the element indexed L to the element indexed R.So, if the input is like [1, 2, 1, 2, 1, 2, ... Read More

Suppose we have a binary tree, we have to find the values of its boundary in anti-clockwise direction starting from root. Here boundary includes left boundary, leaves, and the right boundary in order without duplicate nodes.The left boundary is the path from root to the left-most node.The Right boundary is the path from root to the right-most node.When the root doesn't have left subtree or right subtree, then the root itself is left boundary or right boundary.So, if the input is likethen the output will be [1, 2, 4, 7, 8, 9, 10, 6, 3]To solve this, we will follow ... Read More

Suppose we have n teams and we always arrange the rather strong team to play with the rather weak team, like make the rank 1 team play with the team with rank n, this strategy is to make the contest more interesting. Now we have to find their final contest matches in the form of a string.These teams are given in the form of positive integers from 1 to n, which represents their initial rank. So, rank 1 is the strongest team, and Rank n is the weakest team. We will use parentheses and commas to represent the contest team ... Read More

Suppose we have a string consisting of parenthesis and integers. We have to construct a binary tree from that string. The whole input represents a binary tree. It holds an integer that followed by zero, one or two pairs of parentheses. The integer represents the root's value and a pair of parenthesis contains a child binary tree with the same structure.So, if the input is like "4(2(3)(1))(6(5))", then the output will be [3, 2, 1, 4, 5, 6] (inorder traversal)To solve this, we will follow these steps −Define a function solve(), this will take s, idx, if idx >= size ... Read More

Suppose we have a picture consisting of black and white pixels, we have to find the number of black pixels, which are present at row R and column C. That is aligned with all the following rules −R and C will contain exactly N black pixelsFor all rows, that have a black pixel at column C, they should be exactly the same as row R.Here the picture is represented by a 2D char array consisting of 'B' and 'W', for the black and white pixels respectively.If the input is like −WBWBBWWBWBBWWBWBBWWWBWBWAnd N = 3, then the output will be 6. ... Read More

Suppose we have a grid, here in each cell can have one of three values −value 0 for an empty cell;value 1 for a fresh orange;value 2 for a rotten orange.In every minute, any fresh orange that is adjacent to a rotten orange becomes rotten.We have to find the minimum number of times that must elapse until no cell has a fresh orange. If this is not possible, then return -1.So, if the input is like [[2, 1, 1], [1, 1, 0], [0, 1, 1]], then the output will be 4To solve this, we will follow these steps −minutes := ... Read More

Suppose we have a binary tree, the root node is present at depth 0, and children of each depth k node are at depth k+1.Here two nodes of a binary tree are called cousins if they have the same depth, but have different parents.All values of the tree will be unique, and the values x and y of two different nodes in the tree. We have to check whether the nodes corresponding to the values x and y are cousins or not.So, if the input is likex = 5, y = 4, then the output will be trueTo solve this, ... Read More

Suppose we are considering an infinite number line, here the position of the i−th stone is given by array stones and stones[i] is indicating ith stone position. A stone is an endpoint stone if it has the smallest or largest position. Now in each turn, we pick up an endpoint stone and move it to an unoccupied position so that it is no longer an endpoint stone.If the stones are at say, stones = [1, 2, 5], we cannot move the endpoint stone at position 5, because moving it to any position (such as 0, or 3) will still keep ... Read More