HDU 5916 Harmonic Value Description

Problem Description

The harmonic value of the permutation p1,p2,⋯pn is

Mr. Frog is wondering about the permutation whose harmonic value is the strictly k-th smallest among all the permutations of [n].

 

Input

The first line contains only one integer T (1≤T≤100), which indicates the number of test cases.

For each test case, there is only one line describing the given integers n and k (1≤2k≤n≤10000).

 

Output

For each test case, output one line “Case #x: p1 p2 ⋯ pn”, where x is the case number (starting from 1) and p1 p2 ⋯ pn is the answer.

 

Sample Input

2

4 1

4 2

 

Sample Output

Case #1: 4 1 3 2

Case #2: 2 4 1 3

 

2016中国大学生程序设计竞赛（长春）-重现赛

 

 题目大意：给定一个数n，k，求出一个序列，使得他的和是第k小的（序列为1-n）

思路: 找出规律即可，当k=1时，直接按顺序输出1-n；k>1时 讲前2*k个数中的偶数和奇数分别放在一起，最后再将2*k+1 --- n 顺序输出即可

#include<iostream>
#include<algorithm>
#include<cstdio>

using namespace std;
int T,n,k;
int main()
{
    scanf("%d",&T);
    for(int t=1;t<=T;t++){
        scanf("%d%d",&n,&k);
        printf("Case #%d:",t);
        if(k>1){
            for(int i=2;i<=2*k;i+=2)
                printf(" %d",i);
            for(int i=1;i<2*k;i+=2)
                printf(" %d",i);
            for(int i=2*k+1;i<=n;i++)
                printf(" %d",i);
        }else{
            for(int i=1;i<=n;i++)
                printf(" %d",i);
        }
        putchar('
');
    }
    return 0;
}