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

UPCOMING CHALLENGES:

Ruthenium 2019

CURRENT CHALLENGES:

Technetium 2019

PAST CHALLENGES

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

respectable

Calculate the number of pairs (P, S) such that {A[0], ..., A[P]} = {A[S], ..., A[N-1]}.

Programming language:

A non-empty array A consisting of N integers is given. A *prefix suffix set* is a pair of indices (P, S) such that 0 ≤ P, S < N and such that:

- every value that occurs in the sequence A[0], A[1], ..., A[P] also occurs in the sequence A[S], A[S + 1], ..., A[N − 1],
- every value that occurs in the sequence A[S], A[S + 1], ..., A[N − 1] also occurs in the sequence A[0], A[1], ..., A[P].

The goal is to calculate the number of prefix suffix sets in the array.

For example, consider array A such that:

There are exactly fourteen prefix suffix sets: (1, 4), (1, 3), (2, 2), (2, 1), (2, 0), (3, 2), (3, 1), (3, 0), (4, 2), (4, 1), (4, 0), (5, 2), (5, 1), (5, 0).

Write a function:

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

that, given a non-empty array A of N integers, returns the number of prefix suffix sets.

If the number of prefix suffix sets is greater than 1,000,000,000, the function should return 1,000,000,000.

For example, given:

the function should return 14, as explained above.

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

- N is an integer within the range [1..40,000];
- each element of array A is an integer within the range [−1,000,000,000..1,000,000,000].

Copyright 2009–2019 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.