Permutation p is an ordered set of integers p 1, p 2, …, p n, consisting of n distinct positive integers not larger than n. We’ll denote as n the length of permutation p 1, p 2, …, p n.
Your task is to find such permutation p of length n, that the group of numbers |p 1 - p 2|, |p 2 - p 3|, …, |p n - 1 - p n| has exactly k distinct elements.
Input
The single line of the input contains two space-separated positive integers n, k (1 ≤ k < n ≤ 105).
Output
Print n integers forming the permutation. If there are multiple answers, print any of them.
Examples
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 number x.
Solution:
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <memory.h>
#include <cassert>
using namespace std;
int a[1234567];
int main() {
int n, k;
scanf("%d %d", &n, &k);
a[0] = 1;
int low = 1, high = 1;
for (int i = 1; i <= k; i++) {
if (i % 2 == 1) {
a[i] = ++high;
} else {
a[i] = --low;
}
}
for (int i = k + 1; i < n; i++) {
if (a[k] == low) {
a[i] = a[i - 1] - 1;
} else {
a[i] = a[i - 1] + 1;
}
}
int smallest = a[0];
for (int i = 1; i < n; i++) {
if (a[i] < smallest) {
smallest = a[i];
}
}
for (int i = 0; i < n; i++) {
if (i > 0) printf(" ");
printf("%d", a[i] - smallest + 1);
}
printf("\n");
return 0;
}
Related posts:
New Year Shopping
Coprime Permutation
Chat Order
Deleting from a data structure in $O(T(n)\log n)$
String Set Queries
Image Preview
Substring Search
Dexterina’s Lab
Dreamoon Likes Strings
Helping People
Ramesses and Corner Inversion
Treap (Cartesian tree)
R3D3’s Summer Adventure
Amity Assessment
Restore Permutation
Rectangle Painting 1
Letters and Question Marks
Purification
Discrete Logarithm
Fox and Perfect Sets
Minimum spanning tree - Kruskal's algorithm
Watchmen
Table Compression
Integration by Simpson's formula
Bear and Two Paths
Kuroni and Simple Strings
Bags and Coins
Beautiful fountains rows
Convex hull trick and Li Chao tree
Paint the Numbers
Dima and Staircase
Niyaz and Small Degrees