SDE - 1

You are given a positive integer 'N'. Your task is to return all the prime numbers less than or equal to the 'N'.

Note:

1) A prime number is a number that has only two factors: 1 and the number itself.

2) 1 is not a prime number.

Given two strings, 'S' and 'T' with lengths 'M' and 'N', find the length of the 'Longest Common Subsequence'.

For a string 'str'(per se) of length K, the subsequences are the strings containing characters in the same relative order as they are present in 'str,' but not necessarily contiguous. Subsequences contain all the strings of length varying from 0 to K.

Example :

Subsequences of string "abc" are:  ""(empty string), a, b, c, ab, bc, ac, abc.

You are given a sorted array 'ARR' and a number 'X'. Your task is to count the number of occurrences of 'X' in 'ARR'.

Note :

1. If 'X' is not found in the array, return 0.
2. The given array is sorted in non-decreasing order.

You have been given a grid containing some oranges. Each cell of this grid has one of the three integers values:

Value 0 - representing an empty cell.

Value 1 - representing a fresh orange.

Value 2 - representing a rotten orange.

Every second, any fresh orange that is adjacent(4-directionally) to a rotten orange becomes rotten.

Your task is to find out the minimum time after which no cell has a fresh orange. If it's impossible to rot all the fresh oranges then print -1.

Note:

1. The grid has 0-based indexing.
2. A rotten orange can affect the adjacent oranges 4 directionally i.e. Up, Down, Left, Right.