Suppose we want to implement one stack called FreqStack, Our FreqStack has two functions −push(x), This will push an integer x onto the stack.pop(), This will remove and returns the most frequent element in the stack. If there are more than one elements with same frequency, then the element closest to the top of the stack is removed and returned.So, if the input is like push some elements like 7, 9, 7, 9, 6, 7, then perform the pop operations four times, then the output will be 7, 9, 7, 6 respectively.To solve this, we will follow these steps −Define ... Read More

Suppose we have an array A of integers, consider all non-empty subsequences of A. For any sequence S, consider the width of S be the difference between the maximum and minimum element of S. We have to find the sum of the widths of all subsequences of A. The answer may be very large, so return the answer modulo 10^9 + 7.So, if the input is like [3, 1, 2], then the output will be 6, this is because the subsequences are like [1], [2], [3], [2, 1], [2, 3], [1, 3], [2, 1, 3] and the widths are 0, ... Read More

Suppose we have given K eggs, and we have a building with N floors from 1 to N. Now each egg is identical in function, and if an egg breaks, we cannot drop it again.There exists a floor F with between 0 and N such that any egg dropped at a floor higher than F will break, and any egg dropped at or below floor F will not break. In each move, we may take an egg and drop it from any floor X. The X is in range 1 to N.Our goal is to know with certainty what the ... Read More

Suppose there is a gang with G people and a list of various crimes they could commit. The i-th crime generates a profit value profit[i] and requires group[i] gang members to participate.If a gang member is participating in one crime, that he can't participate in another crime. Now let us define profitable scheme any subset of these crimes that generates at least P profit, and total number of members participating in that subset of crimes is at most G.We have to find how many schemes can be chosen? The answer may be very large, So return it modulo 10^9 + ... Read More

Suppose there is a car, that travels from a starting position to a destination which is t miles east of the starting position.Now along the way, there are many gas stations. So each station[i] represents a gas station that is station[i][0] miles east of the starting position, and that station has station[i][1] liters of gas.If the car starts with an infinite size of gas tank, which initially has startFuel liters of fuel in it. It uses 1 liter of gas per 1 mile that it drives.When the car reaches one gas station, it may stop and refuel, so now it ... Read More

Suppose we have an array A. We have to find the length of the shortest, non-empty, contiguous subarray of A whose sum is at least K. If there is no such subarray, then return -1.So, if the input is like [5, 3, -2, 2, 1] and k = 6, then the output will be 2, as we can see (5+3) >= 6To solve this, we will follow these steps −n := size of Aans := n + 1, j := 0, sum := 0Define one deque dqfor initialize i := 0, when i < n, update (increase i by 1), ... Read More

Suppose there are N workers. Each worker has the quality parameter. The i-th worker has a quality[i] and a minimum wage expectation wage[i]. Now we want to hire K workers to form a paid group. When we are hiring a group of K workers, we must pay them according to the following rules −Each worker in the paid group should be paid in the ratio of their quality by comparing with others in the paid group.Every worker in the paid group must be paid at least their minimum wage expectation.We have to find the least amount of money needed to ... Read More

Suppose we have two strings A and B. These two strings are K-similar (where K is one nonnegative integer) if we can swap the positions of two letters in A exactly K times so that the resulting string is B. So, we have two anagrams A and B, we have to find the smallest K for which A and B are K-similar.So, if the input is like A = "abc", B = "bac", then the output will be 2.To solve this, we will follow these steps −Define a function swapp(), this will take string s, i, j, x := s[i], ... Read More

Suppose we have one undirected, connected graph with N nodes these nodes are labeled as 0, 1, 2, ..., N-1. graph length will be N, and j is not same as i is in the list graph[i] exactly once, if and only if nodes i and j are connected. We have to find the length of the shortest path that visits every node. We can start and stop at any node, we can revisit nodes multiple times, and we can reuse edges.So, if the input is like [[1], [0, 2, 4], [1, 3, 4], [2], [1, 2]], then the output ... Read More

Suppose we have two strings X and Y, these are similar if we can swap two letters of X, so that it equals Y. Also two the strings X and Y are similar if they are equal. As an example, consider, two strings are like "tars" and "rats" are similar, if we swap t and r, then we can find another, now "rats" and "arts" are similar, but "star" is not similar to "tars", "rats", or "arts". Now we can see, these form two connected groups by similarity: {"tars", "rats", "arts"} and {"star"}. Here "tars" and "arts" are in the ... Read More