HDU 5916: Harmonic Value Description

题目描述

The harmonic value of the permutation $p_1,p_2,cdots p_n$ is
$$sum_{i=1}^{n-1} gcd(p_i.p_{i+1})$$
Mr. Frog is wondering about the permutation whose harmonic value is the strictly k-th smallest among all the permutations of [n].

输入

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

For each test case, there is only one line describing the given integers n and k ($1leq 2k leq n leq10000$).

输出

For each test case, output one line “Case #x: $p_1 p_2 cdots p_n$”, where x is the case number (starting from 1) and $p_1 p_2 cdots p_n$ is the answer.

样例输入

2

4 1

4 2

样例输出

Case #1: 4 1 3 2

Case #2: 2 4 1 3

分析：按要求，gcd(i,i+1)=1，gcd(k,2*k)=k。

#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
#include <deque>
#include <map>
#define range(i,a,b) for(int i=a;i<=b;++i)
#define LL long long
#define rerange(i,a,b) for(int i=a;i>=b;--i)
#define fill(arr,tmp) memset(arr,tmp,sizeof(arr))
using namespace std;
int t;
void init() {
    cin>>t;
}
void solve(){
    int cas=0;
    while(t--){
        int n,k;
        cin>>n>>k;
        cout<<"Case #"<<++cas<<": "<<(k<<1)<<" "<<k;
        range(i,k+1,n){
            if(i==(k<<1))continue;
            cout<<" "<<i;
        }
        range(i,1,k-1)cout<<" "<<i;
        cout<<endl;
    }
}
int main() {
    init();
    solve();
    return 0;
}