ProblemA magical string str consists of only '1' and '2' and obeys the following rules −The string str is magical because concatenating the number of contiguous occurrences of characters '1' and '2' generates the string str itself.The first few elements of string str is the following −str = "1221121221221121122……"If we group the consecutive '1's and '2's in str, it will be −1 22 11 2 1 22 1 22 11 2 11 22 ......and the occurrences of '1's or '2's in each group are −1 2 2 1 1 2 1 2 2 1 2 2 ......We can see that ... Read More

ProblemWe are required to write a JavaScript function that takes in a string str, as the first argument and an Integer, n as the second argument. The string str is composed of alphanumeric characters and dashes.The dashes split the alphanumeric characters within the string into groups. (i.e. if there are n dashes, the string is split into n+1 groups). The dashes in the given string are possibly misplaced.We want each group of characters to be of length K (except for possibly the first group, which could be shorter, but still must contain at least one character).To satisfy this requirement, we ... Read More

Good BaseFor an integer num, we call k (k >= 2) a good base of num, if all digits of num base k are 1.For instance: 13 base 3 is 111, hence 3 is a good base for num = 13ProblemWe are required to write a JavaScript function that takes in string str that represents a number as the only argument. The function should return the string representation of the smallest possible number which is a good base for str.For example, if the input to the function is −const str = "4681";Then the output should be −const output = "8";Output ... Read More

ProblemWe are required to write a JavaScript function that takes in a binary array (an array that consists of only 0 and 1), arr, as the only argument. Our function should find the maximum number of consecutive 1s in this array if we can flip at most one 0.For example, if the input to the function is −const arr = [1, 0, 1, 1, 0];Then the output should be −const output = 4;Output ExplanationIf we flip the 0 at index 1 in the array, we will get 4 consecutive 1s.ExampleThe code for this will be − Live Democonst arr = [1, ... Read More

ProblemWe are required to write a JavaScript function that takes in an array of Integers, arr, as the first and the only argument.Our function should count the occurrence of all such index pairs (i, j) that satisfy the following conditions −I < j, andarr[i] > 2 * arr[j]For example, if the input to the function is −const input = [2, 4, 3, 5, 1];Then the output should be −const output = 3;Output Explanation:Because the three desired pairs are −[4, 1], [3, 1] and [5, 1]ExampleThe code for this will be − Live Democonst arr = [2, 4, 3, 5, 1]; const ... Read More

ProblemWe are required to write a JavaScript function that takes in an array of Integers, arr, as the first argument and a single integer, target, as the second argument.For each Integer in the array, our function can either assign ‘+’ or ‘-’ to it.Our function should find out how many ways in total exist to assign ‘+’, ‘-’ to make the sum of integers of the array equal to the target sum, target.For example, if the input to the function is −const arr = [1, 1, 1, 1, 1]; const target = 3;Then the output should be −const output = ... Read More

Problem:We are required to write a JavaScript function that takes in a square matrix (an array of arrays having the same number of rows and columns). The function should traverse diagonally through that array of array and prepare a new array of elements placed in that order it encountered while traversing.For example, if the input to the function is −const arr = [    [1, 2, 3],    [4, 5, 6],    [7, 8, 9] ];Then the output should be −const output = [1, 2, 4, 7, 5, 3, 6, 8, 9];Example Live DemoThe code for this will be −const arr ... Read More

Mode:Mode of a set of data is simply the number that occurs for most number of times in that set of data. For instance, 3 is the mode of dataset 2, 3, 1, 3, 4, 2, 3, 1 as it occurs for most number of times.Binary Search TreeA tree DS is a valid Binary Search Tree if it fulfils the following conditions −The left subtree of a node contains only nodes with keys less than or equal to the node's key.The right subtree of a node contains only nodes with keys greater than or equal to the node's key.Both the ... Read More

Circular ArrayAn array in which the next element of the last element is the first element of the array is often termed as circular.Obviously, there exists no such mechanism to store data like this, data will still be stored in continuous memory blocks and circular arrays are more like an idea than reality.ProblemWe are required to write a JavaScript function that takes in a circular array of Integers, arr, as the first and the only argument.The function should then construct and return an array that contains the next greater element for each corresponding element of the original array. The Next ... Read More

ProblemWe are required to write a JavaScript function that takes in an array, arr, of numbers as the only argument.The array basically consists of the marks scored by some students, based on the array of marks, our function should prepare and return an array of ranks which should contain the rank of corresponding students on the basis of how high their marks are in the marks array arr.For instance, for the highest entry in array arr, the corresponding entry in output array should be 1, 2 for second highest and so on.For example, if the input to the function is ... Read More