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  1. Prepare
  2. Algorithms
  3. Implementation
  4. Absolute Permutation
  5. Discussions

Absolute Permutation

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526 Discussions

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  • alex_k5
     + 1 comment

    Python

    def absolutePermutation(n, k):

    if k !=0 and n% (2*k) !=0:
    return [-1]
if k == 0:
    return list(range(1, n+1))
return [(u + k if (u-1) % (2*k) + 1 <= k else u - k) for u in range(1, n+1)]

  • dhihanlaksanaaj1
     + 0 comments

    swift

    func absolutePermutation(n: Int, k: Int) -> [Int] {
    var results: [Int] = [Int]()
    var isUpper: Bool = false
    
    if k == 0 { return Array(1 ... n) }
    
    for number in 0 ... n - 1 {        
        if number % k == 0 { isUpper = !isUpper }
        
        if isUpper { results.append((number + 1) + k) }
        else { results.append((number + 1) - k) }
    
        if results.last! > n { return [-1] }
    }
    return results
}

  • jmcparland
     + 0 comments

    Haskell

    module Main where

import Control.Monad (replicateM_)
import qualified Data.Set  as S

solve :: Int -> Int -> Maybe [Int]
solve n k = go S.empty [] [1 .. n]
  where
    go _ acc [] = Just $ reverse acc
    go used acc (x : xs)
        | x - k >= 1
            && (x - k) `S.notMember` used =
            go (S.insert (x - k) used) (x - k : acc) xs
        | x + k <= n
            && (x + k) `S.notMember` used =
            go (S.insert (x + k) used) (x + k : acc) xs
        | otherwise = Nothing

main :: IO ()
main = do
    cases <- readLn :: IO Int
    replicateM_ cases $ do
        [n, k] <- map read . words <$> getLine :: IO [Int]
        case solve n k of
            Just ps -> putStrLn $ unwords $ map show ps
            Nothing -> putStrLn "-1"

  • kheengz
     + 0 comments

    Typescript

    let map: Map<number, number> = new Map();
    for(let i = 1; i <= n; i++) {
        if (i - k > 0 && !map.has(i - k)) {
            map.set(i - k, i);
        } else if (i + k <= n) {
            map.set(i + k, i);
        } else{
            return [-1];
        }
    }
    return [...map.keys()];

  • AbdelrhmanAdawy
     + 1 comment

    I think there is wrong answer in test case n = 69660 and k = 1620 this shouldn't be -1, why test case #12 shows it -1 ?

    this my code in c

    int* absolutePermutation(int n, int k, int* result_count) {
    
    int * pos = calloc(n, sizeof(int)) , i = 0;
    
    if(k == 0)
    {
        for( i = 0 ; i<n ; i++)
        {
            pos[i] = i+1;   
        }
        *result_count = n;
    }
    else if( ( (n%2 == 0) && (n%k == 0) && (n != k)))
    {
        for(i = 0 ; i<n ; i++)
        {
            if ( (i/k)%2 == 0 ) {
                pos[i] = (i+1+k);          
            }
            else
            {
                pos[i] = (i+1-k);
            }
        }   
        
        *result_count = n;
    }
    else {
        pos = realloc(pos, sizeof(int));
        pos[0] = -1;
        * result_count = 1;
    }
    
    return pos;
}