cyclic rotation codility c++ solution

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I am trying to solve this problem in Codility... Here is the code:

 #include <iostream>    
 #include <vector>     
 #include <algorithm>
 using namespace std;

 vector<int> solution(vector<int> &A, int k);
 vector<int> A;   
 A.push_back(3);    
 A.push_back(5);   
 A.push_back(7);   
 A.push_back(9);   
 A.push_back(2);
 int k;
 rotate(A.rbegin(),A.rbegin()+k, A.rend());

While my compiler compiles and run with no problem, codility shows me that "error: 'A' does not name a type". This is the code using to my compiler to check it:

  #include <iostream>
  #include <vector>
  #include <algorithm>
  using namespace std;

  int main()
  {
   vector<int> myVector;
   myVector.push_back(3);
   myVector.push_back(5);
   myVector.push_back(7);
   myVector.push_back(9);
   myVector.push_back(2);
   for(unsigned i=0;i<myVector.size();i++)
   {
     cout<<myVector[i]<<" ";
   }
   cout<<endl;
   int k;
   cout<<"Insert the times of right rotation:";
   cin>>k;
   rotate(myVector.rbegin(),myVector.rbegin()+k, myVector.rend());
   for(unsigned i=0;i<myVector.size();i++)
   {
     cout<<myVector[i]<<" ";
   }
  }

Compiler output:

func.cpp:9:3: error: 'A' does not name a type
   A.push_back(3);
   ^
func.cpp:10:3: error: 'A' does not name a type
   A.push_back(5);
   ^
func.cpp:11:3: error: 'A' does not name a type
   A.push_back(7);
   ^
func.cpp:12:3: error: 'A' does not name a type
   A.push_back(9);
   ^
func.cpp:13:3: error: 'A' does not name a type
   A.push_back(2);
   ^
func.cpp:16:9: error: expected constructor, destructor, or type conversion before '(' token
   rotate(A.rbegin(),A.rbegin()+k, A.rend());
         ^
func.cpp:18:1: error: expected declaration before '}' token
 }
 ^

Detected some errors.

I think you had lot of problem and made some assumption Here is the working code

1.You don't need to create a new vector as the function has already a referenced vector &A so any change will directly reflect to the original vector

2.value K is points of rotation which is already input to the function (so no need of cin)

got it 100% now

// you can use includes, for example:
// #include <algorithm>

// you can write to stdout for debugging purposes, e.g.
// cout << "this is a debug message" << endl;
#include<algorithm>


vector<int> solution(vector<int> &A, int K)
{
    if (A.empty() || A.size() == 1)
    {
        return A;
    }
    K = K % A.size();

    if (K == 0)
    {
        return A;
    }
    std::rotate(A.rbegin(), A.rbegin() + K, A.rend());
    return A;
}

Output

Codility solution: Cyclic Rotation, Codility solution: Cyclic Rotation. You are to rotate an array of N integers K integers to the right. In this exercise time Language: C. Assumptions. N, K may​  You could see a rotation as copying 2 sections from one array to another given a pivot. Check out this article about the subject. If you can change the signature, make a static class with static method, use a meaningful method name RotateRight with arguments array and count and make it clear whether in-place rotation is performed or a new array


OBJECTIVE-C SOLUTION O(n*k) - One By One Approach

Results given by Codility

Task Score: 100% Correctness: 100% Performance: Not assesed

Time Complexity

The worst case time complexity is O(n*k)

Xcode Solution Here

+(NSMutableArray*)byByOneSolution:(NSMutableArray*)array rotations:(int)k {
    // Checking for edge cases in wich the array doesn't change.
    if (k == 0 || array.count <= 1) {
        return array;
    }

    // Calculate the effective number of rotations
    // -> "k % length" removes the abs(k) > n edge case
    // -> "(length + k % length)" deals with the k < 0 edge case
    // -> if k > 0 the final "% length" removes the k > n edge case
    NSInteger n = array.count;
    NSInteger rotations = (n  + k % n ) % n;


    /******** Algorithm Explanation: Naive Method ********/
    // Rotate one by one based on the efective rotations
    for (int i = 0; i < rotations; i++) {
        id last = array[n-1];
        [array removeLastObject];
        [array insertObject:last atIndex:0];
    }
    return array;
}

codility-lesson-solutions/solution.c at master · ghanan94/codility , codility-lesson-solutions/Lesson 02 - Arrays/CyclicRotation/solution.c. Find file Copy path. Fetching contributors… Cannot retrieve contributors at this time. An array A consisting of N integers is given. Rotation of the array means that each element is shifted right by one index, and the last element of the array is moved to the first place. For example, the rotation of array A = [3, 8, 9, 7, 6] is [6, 3, 8, 9, 7] (elements are shifted right by one index and 6 is moved to the first place).


If you don't want to use rotate function from <algorithm>.

Results given by Codility:

Programming : C++
Task Score: 100%
Correctness: 100%
Performance: Not assesed

The solution:

vector<int> solution(vector<int> &A, int K)
{
    vector <int> shift;
    if (A.empty()) // check for empty array
        return {};
    if (K > A.size()) //if K bigger then size of array 
        K = K%A.size();
    if (K<A.size())
        K=A.size()-K; //normalize K to the position to start the shifted array
    if (K == A.size()) //if K= size of array, avoid any computation.
        return A;
    for (unsigned int i=K; i<A.size(); i++)
    {
        shift.push_back(A[i]);
    }
    for (unsigned int i=0; i<K; i++)
    {
        shift.push_back(A[i]);
    }
    return shift;
}

Codility Cyclic rotation in C#, The exercise is from codility . The goal is to rotate array A K times; that is, each element of A will be shifted to the right K times. that, given an array A consisting of N integers and an integer K, returns the array A rotated K times. Java solution to Codility CyclicRotation problem (Lesson 2 – Arrays) which scored 100%. The problem is to rotate an integer array K times to the right and calculate what the final array will look like. The main strategy is to use the mod operator to calculate final index after wrapping around end of array. 123456789101112131415package …


You can only define or declare symbols outside function. Your A.push_back(3); etc is not a definition or declaration statement. That's why you get the funny error message: definitions and declarations start with a type, and since the lines are outside of function, compiler expects to see a type, which A is not.

So you need a function, something like:

#include <iostream>    
#include <vector>     
#include <algorithm>
using namespace std;

vector<int> solution(vector<int> &A, int k)
{ //added
    //vector<int> A; // this is function argument, not local variable   
    A.push_back(3);    
    A.push_back(5);   
    A.push_back(7);   
    A.push_back(9);   
    A.push_back(2);
    //int k;  // this is function argument, not local variable
    rotate(A.rbegin(),A.rbegin()+k, A.rend());
    return A; // Added since the function needs to return a vector of int...
} //added

That should compile and do something. So what I did was what you probably intended to do: The code is in solution function now.

CyclicRotation coding task - Learn to Code, CyclicRotation · START. Rotate an array to the right by a given number of steps. Programming language: C, C++, C#, Go, Java 11, Java 8, JavaScript, Kotlin, Lua​  Short Problem Definition: Rotate an array to the right by a given number of steps. Link Cyclic Rotation Complexity: expected worst-case time complexity is O(N) Execution: There are multiple solutions to this problem.


OBJECTIVE-C SOLUTION O(n) - Reverse Based Solution

Results given by Codility

Task Score: 100% Correctness: 100% Performance: Not assesed

Time Complexity

The worst case time complexity is O(3n) => O(n)

Xcode Solution Here

+(NSMutableArray*)reverseBasedsolution:(NSMutableArray*)array rotations:(int)k {

    // Checking for edge cases in wich the array doesn't change.
    if (k == 0 || array.count <= 1) {
        return array;
    }

    // Calculate the effective number of rotations
    // -> "k % length" removes the abs(k) > n edge case
    // -> "(length + k % length)" deals with the k < 0 edge case
    // -> if k > 0 the final "% length" removes the k > n edge case
    NSInteger n = array.count;
    NSInteger rotations = (n  + k % n ) % n;

    /******** Algorithm Explanation: Reverse Based ********/
    // 1.- Reverse the whole array
    // 2.- Reverse first k numbers
    // 3.- Reverse last n-k numbers

    // 1. Reverse the whole array
    NSArray* reversed = [[array reverseObjectEnumerator] allObjects];

    // 2. Reverse first k numbers
    NSRange leftRange = NSMakeRange(0, rotations);
    NSArray* leftPart = [[[reversed objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:leftRange]] reverseObjectEnumerator] allObjects];

    // 3. Reverse last n-k numbers
    NSRange rightRange = NSMakeRange(rotations, n - rotations);
    NSArray* rightPart = [[[reversed objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:rightRange]] reverseObjectEnumerator] allObjects];

    // Replace objects in the original array
    [array replaceObjectsInRange:leftRange withObjectsFromArray:leftPart];
    [array replaceObjectsInRange:rightRange withObjectsFromArray:rightPart];

    return  array;
}

CyclicRotation - Codility - Solution, Java solution to Codility CyclicRotation problem (Lesson 2 – Arrays) which scored 100%. The problem is to rotate an integer array K times to the right and  codility cyclic rotation coding problem A zero-indexed array A consisting of N integers is given. Rotation of the array means that each element is shifted right by one index, and the last element of the array is also moved to the first place.


Codility, Codility - CyclicRotation Rotation of the array means that each element is shifted right by one index, and the last element of the array is also  cyclic rotation codility c++ solution. Ask Question Asked 2 years, 4 months ago. Active 1 month ago. Viewed 888 times 0. I am trying to


Solution to Cyclic-Rotation by codility – Code Says, Also another Python solution with the same method as @micropentium6's can be found in an older post. C/C++, Codility, Python. 32 Replies to “  .Net Framework interview questions and answers Asp.Net Asp.net mvc Auto Responder Binary Gap C# C# Concepts C# For Loop exception Codility Codility Cyclic Rotation Solution C# Codility FrogJmp Solution Codility OddOccurrencesInArray Solution C#.Net Codility TapeEquilibrium Solution C# Common table expression CSS Delegates in C#.Net Entity


2.1 CyclicRotation - James Chen's C/C++ Home, A collection of C/C++ software developer interview questions. CyclicRotation · VIEW START Output. https://codility.com/demo/results/trainingRYQVY7-92R/  © 2009–2020 Codility Ltd., registered in England and Wales (No. 7048726). VAT ID GB981191408. Registered office: 107 Cheapside, London EC2V 6DN