SDE - 1

Given an array arr of length N consisting of positive and negative integers, return the length of the longest subarray whose sum is zero.

You are given an array/list NUM of integers. You are supposed to rearrange the elements of NUM such that no two adjacent elements will be the same or find out if it not possible.

For example:

Input: arr[] = {1,1,1,2,2,2} 
Output: {1,2,1,2,1,2}

Note: {2,1,2,1,2,1} is also valid because there are no two adjacent elements which are the same.

You have been given a number of stairs. Initially, you are at the 0th stair, and you need to reach the Nth stair.

Each time, you can climb either one step or two steps.

You are supposed to return the number of distinct ways you can climb from the 0th step to the Nth step.

Note:

Note: Since the number of ways can be very large, return the answer modulo 1000000007.

Example :

N=3

We can climb one step at a time i.e. {(0, 1) ,(1, 2),(2,3)} or we can climb the first two-step and then one step i.e. {(0,2),(1, 3)} or we can climb first one step and then two step i.e. {(0,1), (1,3)}.