Skip to main content

Least jump to reach array end

Given an array of Integers arr,
from an element val = arr[i], you can go to element i to i+val.
If val is zero, you cannot move forward.
find the least selection to reach end of the array.

example: 1 3 5 8 9 2 6 7 6 8 9
@index 0, can go to 1
@index 1, can go to 4.
if index 3 and 4 choosen, it will reach to end frm there only.

Give an algorithm and program.

This can be solved with greedy aproach.

Assume we are at index i,
So For all i ..to i+a[i] index check for the max value value
of k+a[k], where i
We can prove the correctness of this .

If k+a[k] having maximum value then any value except the k in range of i to i+a[i]
will be less than range reachable by k.
So by choosing k, you still can choose the option available with other indexs.
Labels:

Comments

Post a Comment

Popular posts from this blog

Car Parking Problem

There is n parking slots and n-1 car already parked. Lets say car parked with initial arrangement and we want to make the car to be parked to some other arrangement. Lets say n = 5, inital = free, 3, 4, 1, 2 desired = 1, free, 2, 4 ,3 Give an algorithm with minimum steps needed to get desired arrangement. Told by one of my friend and after a lot of search i really got a nice solution. I will post solution in comment part
3 comments
Read more

DEShaw Interview Questions

ther are N numbers frm 1 to N and starting from index 1 we will keep deleting every alternate going in cyclic order with array. Only one element will be left at the end. Tell us the index of element in array we started. e.g. there are 5 nums 1 2 3 4 5 then after 1st iteration 1 3 5 will be remained. .. then 1 will be next to be elliminated and then 5 3 will remain alone... give sum efficient algorithm to calculate which numer will remain at the end Answer: 2*(n-2^p)+1 where p=floor(log2 n)
Post a Comment
Read more

Scaling application

 We all wish that our application used by maximum people on Earth. To make sure we have the right scalable application, please follow below guidelines  1. Load balancing at all level of application i.e. web server, application server and DB server 2. Remote caching to be enabled for a fast response.  3. Load balancer will equally distribute the traffic to existing servers, what if enough capacity is not enough. We should have a mechanism to increase the server capacity (esp horizontally ).  All the cloud service provider has provision for autoscaling, so do Kubernetes.  Use them.  4. Most of the NoSQL DB comes with good support for horizontal scalability. So if you chosse NoSQL you can easily scale them. But if your application requires RDBMS (SQL) then plan should be with sharding in place.  5. Server should be stateless. Any server should be able to serve an incoming request. No local storage, no IP binding. Having said newly added server will start ...
Post a Comment
Read more