SDE - 1

You are given a positive integer 'N’. Your task is to find and return the minimum number of steps that 'N' has to take to get reduced to 1.

You can perform any one of the following 3 steps:

1) Subtract 1 from it. (n = n - ­1) ,
2) If n is divisible by 2, divide by 2.( if n % 2 == 0, then n = n / 2 ) ,
3) If n is divisible by 3, divide by 3. (if n % 3 == 0, then n = n / 3 ).

For example:

Given:
‘N’ = 4, it will take 2 steps to reduce it to 1, i.e., first divide it by 2 giving 2 and then subtract 1, giving 1.

You are given a string 'str' of length 'N'.

Your task is to return the longest palindromic substring. If there are multiple strings, return any.

A substring is a contiguous segment of a string.

For example :

str = "ababc"

The longest palindromic substring of "ababc" is "aba", since "aba" is a palindrome and it is the longest substring of length 3 which is a palindrome. 

There is another palindromic substring of length 3 is "bab". Since starting index of "aba" is less than "bab", so "aba" is the answer.

You are given a string ‘text’ and a string ‘pattern’, your task is to find all occurrences of pattern in the string ‘text’ and return an array of indexes of all those occurrences. You may assume that the length of ‘text’ is always greater than the length of ‘pattern’.

For example :

Let text = “this is a good place to have a good start”, pattern = “good” so you have to return {10, 31} because at 10 and 31 index pattern is present in the text.

Note :

If there is no such index in the text then just return an array containing -1.

Given that integers are read from a data stream. Your task is to find the median of the elements read so far.

Median is the middle value in an ordered integer list. If the size of the list is even there is no middle value. So the median is the floor of the average of the two middle values.

For example :

[2,3,4] - median is 3.
[2,3] - median is floor((2+3)/2) = 2.

Consider a directed graph of ‘N’ nodes where each node is labeled from ‘0’ to ‘N - 1’. Each edge of the graph is either ‘red’ or ‘blue’ colored. The graph may contain self-edges or parallel edges. You are given two arrays, ‘redEdges’ and ‘blueEdges’, whose each element is of the form [i, j], denoting an edge from node ‘i’ to node ‘j’ of the respective color.

Your task is to compute an array ‘answer’ of size ‘N’, where ‘answer[i]’ stores the length of the shortest path from node ‘0’ to node ‘i’ such that the edges along the path have alternate colors. If there is no such path from node ‘0’ to ‘i’, then ‘answer[i] = -1’.

Example:

N = 4, redEdges = [[0, 1], [2, 3]], blueEdges = [[1, 2], [1, 3]]

The shortest paths for each node from node ‘0’ are:
1: 0->1         Length: 1
2: 0->1->2      Length: 2
3: 0->1->3      Length: 2
So, the ‘answer’ array will be: [0, 1, 2, 2].

Note:

1. The given graph could be a disconnected graph.

2. Any two nodes ‘i’ and ‘j’ can have at most one red edge from ‘i’ to ‘j’ and at most one blue edge from ‘i’ to ‘j’.

You are given 'N' rectangular buildings in a 2-dimensional city. Your task is to compute the skyline of these buildings, eliminating hidden lines return the skyline formed by these buildings collectively. A city's skyline is the outer contour of the silhouette formed by all the buildings in that city when viewed from a distance. The geometric information of each building is given in the array of buildings where BUILDINGS[i] = [LEFT_i, RIGHT_i, HEIGHT_i]:

-> LEFT_i is the x coordinate of the left edge of the ith building.

-> RIGHT_i is the x coordinate of the right edge of the ith building.

-> HEIGHT_i is the height of the ith building.

You may assume all buildings are perfect rectangles grounded on an absolutely flat surface at height 0.

The skyline should be represented as a list of "key points" sorted by their x-coordinate in the form [[x1, y1], [x2, y2], ...]. Each key point is the left endpoint of some horizontal segment in the skyline except the last point in the list, which always has a y-coordinate 0 and is used to mark the skyline's termination where the rightmost building ends. Any ground between the leftmost and rightmost buildings should be part of the skyline's contour.

Note:

There must be no consecutive horizontal lines of equal height in the output skyline. For instance, [...,[2 3], [4 5], [7 5], [11 5], [12 7],...] is not acceptable; the three lines of height 5 should be merged into one in the final output.

As such: [..., [2 3], [4 5], [12 7],...]. 

Also, the buildings are sorted by a non-decreasing order.

For more clarification see sample case 1.