Your browser (Unknown 0) is no longer supported. Some parts of the website may not work correctly. Please update your browser.

UPCOMING CHALLENGES:

Pair a Coder

CURRENT CHALLENGES:

Code Alone

PAST CHALLENGES

Gamer's

Spooktober

National Coding Week

The Coder of Rivia

Fast & Curious

The Fellowship of the Code

May the 4th

The Great Code Off 2021

The Doge 2021

The Matrix 2021

The OLX Group challenge

Silver 2020

Palladium 2020

Rhodium 2019

Ruthenium 2019

Technetium 2019

Molybdenum 2019

Niobium 2019

Zirconium 2019

Yttrium 2019

Strontium 2019

Rubidium 2018

Arsenicum 2018

Krypton 2018

Bromum 2018

Future Mobility

Grand Challenge

Digital Gold

Selenium 2018

Germanium 2018

Gallium 2018

Zinc 2018

Cuprum 2018

Cutting Complexity

Nickel 2018

Cobaltum 2018

Ferrum 2018

Manganum 2017

Chromium 2017

Vanadium 2016

Titanium 2016

Scandium 2016

Calcium 2015

Kalium 2015

Argon 2015

Chlorum 2014

Sulphur 2014

Phosphorus 2014

Silicium 2014

Aluminium 2014

Magnesium 2014

Natrium 2014

Neon 2014

Fluorum 2014

Oxygenium 2014

Nitrogenium 2013

Carbo 2013

Boron 2013

Beryllium 2013

Lithium 2013

Helium 2013

Hydrogenium 2013

Omega 2013

Psi 2012

Chi 2012

Phi 2012

Upsilon 2012

Tau 2012

Sigma 2012

Rho 2012

Pi 2012

Omicron 2012

Xi 2012

Nu 2011

Mu 2011

Lambda 2011

Kappa 2011

Iota 2011

Theta 2011

Eta 2011

Zeta 2011

Epsilon 2011

Delta 2011

Gamma 2011

Beta 2010

Alpha 2010

Determine the number of disks that fit into the well.

There is an old dry well. Its sides are made of concrete rings. Each such ring is one meter high, but the rings can have different (internal) diameters. Nevertheless, all the rings are centered on one another. The well is N meters deep; that is, there are N concrete rings inside it.

You are about to drop M concrete disks into the well. Each disk is one meter thick, and different disks can have different diameters. Once each disk is dropped, it falls down until:

- it hits the bottom of the well;
- it hits a ring whose internal diameter is smaller then the disk's diameter; or
- it hits a previously dropped disk.

(Note that if the internal diameter of a ring and the diameter of a disk are equal, then the disk can fall through the ring.)

The disks you are about to drop are ready and you know their diameters, as well as the diameters of all the rings in the well. The question arises: how many of the disks will fit into the well?

Write a function:

class Solution { public int solution(int[] A, int[] B); }

that, given two arrays of integers − A, containing the internal diameters of the N rings (in top-down order), and B, containing the diameters of the M disks (in the order they are to be dropped) − returns the number of disks that will fit into the well.

For example, given the following two arrays:

the function should return 4, as all but the last of the disks will fit into the well. The figure shows the situation after dropping four disks.

Write an ** efficient** algorithm for the following assumptions:

- N and M are integers within the range [1..200,000];
- each element of arrays A and B is an integer within the range [1..1,000,000,000].

Copyright 2009–2022 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.