Codeforces: diverse permutation (query rule)

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Original works, from the "Xiaofeng residual month XJ" blog, welcome to reprint, reprint please be sure to indicate the source (http://blog.csdn.net/xiaofengcanyuexj ).

For various reasons, there may be many shortcomings. Thank you!

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Time limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard output

PermutationPIs an ordered set of IntegersP_{1 ,???P2 ,???...,???PN, ConsistingNDistinct positive integers not largerN. We'll denoteNThe length of permutationP1 ,???P2 ,???...,???PN.}

Your task is to find such PermutationPOf LengthN, That the group of numbers |P_{1? -?P2 | ,? |P2? -?P3 | ,?...,? |PN? -? 1? -?PN| Has exactlyKDistinct elements.}

Input

The single line of the input contains two space-separated Positive IntegersN,K(1? ≤?K? <?N? ≤? 10^{5 ).}

Output

PrintNIntegers forming the permutation. If there are multiple answers, print any of them.

Sample test (s) Input

3 2

Output

1 3 2

Input

3 1

Output

1 2 3

Input

5 2

Output

1 3 2 4 5

Note

By |X| We denote the absolute value of numberX.

Question:

This question requires that a sequence of 1 to n be given, and the number of absolute values that meet the difference between two adjacent items is K. Given 1? ≤?K? <?N? ≤? 10^{Because the five fields are large, you can only search for algorithms with the time complexity of O (n. We can think of this sequence with a maximum of N-1 adjacent differences (absolute values), one of which meets the condition of the sequence is: N, 1, n-1, 2, n-3, 3 ............. You can try to construct a front K-1 that meets the conditions, and then fill in the order that follows.}

Java source code:

 

import java.util.Scanner;public class Main {private int k, n;public Main(int tn, int tk) {n = tn;k = tk;}public void printMain() {boolean flag = true;int count = k - 1;int i = 1;while (count > 0) {if (count != k - 1) {--count;if (count <= 0) {flag = false;break;}System.out.print(" ");}System.out.print(i);System.out.print(" " + (n - i + 1));++i;--count;}int j = n - i + 1;if (count != k - 1 && i <= j)System.out.print(" ");if (flag) {while (i <= j) {System.out.print(j);--j;if (i <= j)System.out.print(" ");}} else {while (i <= j) {System.out.print(i);++i;if (i <= j)System.out.print(" ");}}System.out.println();}public static void main(String[] args) {Scanner input = new Scanner(System.in);while (input.hasNext()) {int tn = input.nextInt();int tk = input.nextInt();Main AC = new Main(tn, tk);AC.printMain();}input.close();}}

Due to time and level, it is inevitable that there are deficiencies. Thank you!

Codeforces: diverse permutation (query rule)