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

AVAILABLE LESSONS:

Lesson 1

Iterations

Lesson 2

Arrays

Lesson 3

Time Complexity

Lesson 4

Counting Elements

Lesson 5

Prefix Sums

Lesson 6

Sorting

Lesson 7

Stacks and Queues

Lesson 8

Leader

Lesson 9

Maximum slice problem

Lesson 10

Prime and composite numbers

Lesson 11

Sieve of Eratosthenes

Lesson 12

Euclidean algorithm

Lesson 13

Fibonacci numbers

Lesson 14

Binary search algorithm

Lesson 15

Caterpillar method

Lesson 16

Greedy algorithms

Lesson 17

Dynamic programming

Lesson 90

Tasks from Indeed Prime 2015 challenge

Lesson 91

Tasks from Indeed Prime 2016 challenge

Lesson 92

Tasks from Indeed Prime 2016 College Coders challenge

Lesson 99

Future training

respectable

Count the minimum number of nails that allow a series of planks to be nailed.

Programming language:
Spoken language:

You are given two non-empty zero-indexed arrays A and B consisting of N integers. These arrays represent N planks. More precisely, A[K] is the start and B[K] the end of the K−th plank.

Next, you are given a non-empty zero-indexed array C consisting of M integers. This array represents M nails. More precisely, C[I] is the position where you can hammer in the I−th nail.

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

The goal is to find the minimum number of nails that must be used until all the planks are nailed. In other words, you should find a value J such that all planks will be nailed after using only the first J nails. More precisely, for every plank (A[K], B[K]) such that 0 ≤ K < N, there should exist a nail C[I] such that I < J and A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Thus, four is the minimum number of nails that, used sequentially, allow all the planks to be nailed.

Write a function:

int solution(int A[], int B[], int N, int C[], int M);

that, given two non-empty zero-indexed arrays A and B consisting of N integers and a non-empty zero-indexed array C consisting of M integers, returns the minimum number of nails that, used sequentially, allow all the planks to be nailed.

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));
- expected worst-case space complexity is O(M), beyond input storage (not counting the storage required for input arguments).

Copyright 2009–2018 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.

You are given two non-empty zero-indexed arrays A and B consisting of N integers. These arrays represent N planks. More precisely, A[K] is the start and B[K] the end of the K−th plank.

Next, you are given a non-empty zero-indexed array C consisting of M integers. This array represents M nails. More precisely, C[I] is the position where you can hammer in the I−th nail.

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

The goal is to find the minimum number of nails that must be used until all the planks are nailed. In other words, you should find a value J such that all planks will be nailed after using only the first J nails. More precisely, for every plank (A[K], B[K]) such that 0 ≤ K < N, there should exist a nail C[I] such that I < J and A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Thus, four is the minimum number of nails that, used sequentially, allow all the planks to be nailed.

Write a function:

int solution(vector<int> &A, vector<int> &B, vector<int> &C);

that, given two non-empty zero-indexed arrays A and B consisting of N integers and a non-empty zero-indexed array C consisting of M integers, returns the minimum number of nails that, used sequentially, allow all the planks to be nailed.

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));
- expected worst-case space complexity is O(M), beyond input storage (not counting the storage required for input arguments).

Copyright 2009–2018 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.

You are given two non-empty zero-indexed arrays A and B consisting of N integers. These arrays represent N planks. More precisely, A[K] is the start and B[K] the end of the K−th plank.

Next, you are given a non-empty zero-indexed array C consisting of M integers. This array represents M nails. More precisely, C[I] is the position where you can hammer in the I−th nail.

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

The goal is to find the minimum number of nails that must be used until all the planks are nailed. In other words, you should find a value J such that all planks will be nailed after using only the first J nails. More precisely, for every plank (A[K], B[K]) such that 0 ≤ K < N, there should exist a nail C[I] such that I < J and A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Thus, four is the minimum number of nails that, used sequentially, allow all the planks to be nailed.

Write a function:

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

that, given two non-empty zero-indexed arrays A and B consisting of N integers and a non-empty zero-indexed array C consisting of M integers, returns the minimum number of nails that, used sequentially, allow all the planks to be nailed.

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));
- expected worst-case space complexity is O(M), beyond input storage (not counting the storage required for input arguments).

Copyright 2009–2018 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

func Solution(A []int, B []int, C []int) int

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

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

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

function solution(A, B, C);

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

function solution(A, B, C)

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

int solution(NSMutableArray *A, NSMutableArray *B, NSMutableArray *C);

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

function solution(A: array of longint; B: array of longint; N: longint; C: array of longint; M: longint): longint;

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

function solution($A, $B, $C);

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

sub solution { my ($A, $B, $C)=@_; my @A=@$A; my @B=@$B; my @C=@$C; ... }

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

def solution(A, B, C)

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

def solution(a, b, c)

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

object Solution { def solution(a: Array[Int], b: Array[Int], c: Array[Int]): Int }

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

public func solution(inout A : [Int], inout _ B : [Int], inout _ C : [Int]) -> Int

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

public func solution(_ A : inout [Int], _ B : inout [Int], _ C : inout [Int]) -> Int

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

We say that a plank (A[K], B[K]) is nailed if there exists a nail C[I] such that A[K] ≤ C[I] ≤ B[K].

For example, given arrays A, B such that:

four planks are represented: [1, 4], [4, 5], [5, 9] and [8, 10].

Given array C such that:

if we use the following nails:

- 0, then planks [1, 4] and [4, 5] will both be nailed.
- 0, 1, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, then planks [1, 4], [4, 5] and [5, 9] will be nailed.
- 0, 1, 2, 3, then all the planks will be nailed.

Write a function:

Private Function solution(A As Integer(), B As Integer(), C As Integer()) As Integer

If it is not possible to nail all the planks, the function should return −1.

For example, given arrays A, B, C such that:

the function should return 4, as explained above.

Assume that:

- N and M are integers within the range [1..30,000];
- each element of arrays A, B, C is an integer within the range [1..2*M];
- A[K] ≤ B[K].

Complexity:

- expected worst-case time complexity is O((N+M)*log(M));

Information about upcoming challenges, solutions and lessons directly in your inbox.

© 2009–2018 Codility Ltd., registered in England and Wales (No. 7048726). VAT ID GB981191408. Registered office: 107 Cheapside, London EC2V 6DN