uva11630 or hdu2987 Cyclic antimonotonic permutations(构造水题)

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Cyclic antimonotonic permutations

Time Limit: 20000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Problem Description

A permutation is a sequence of integers which contains each integer from 1 to n exactly once. In this problem we are looking for permutations with special properties: 

1. Antimonotonic: for each consecutive 3 values p_i-1, p_i, p_i+1 (1 < i < n), p_i should either be the smallest or the biggest of the three values. 
2. Cyclic: The permutation should consist of only one cycle, that is, when we use p_i as a pointer from i to p_i, it should be possible to start at position 1 and follow the pointers and reach all n positions before returning to position 1. 

 

Input

The input file contains several test cases. Each test case consists of a line containing an integer n, (3 ≤ n ≤ 10⁶), the number of integers in the permutation. Input is terminated by n=0. 

 

Output

For each test case print a permutation of the integers 1 to n which is both antimonotonic and cyclic. In case there are multiple solutions, you may print any one. Separate all integers by whitespace characters.

 

Sample Input

3 5 10 0

 

Sample Output

3 1 2 4 5 2 3 1 6 10 2 9 3 5 4 7 1 8

 

Source

2009/2010 Ulm Local Contest

分奇数和偶数，随便搞一下

hdu由于没有special judge，无法AC

//#####################
//Author:fraud
//Blog: http://www.cnblogs.com/fraud/
//#####################
#include <iostream>
#include <sstream>
#include <ios>
#include <iomanip>
#include <functional>
#include <algorithm>
#include <vector>
#include <string>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <climits>
#include <cctype>
using namespace std;
#define XINF INT_MAX
#define INF 0x3FFFFFFF
#define MP(X,Y) make_pair(X,Y)
#define PB(X) push_back(X)
#define REP(X,N) for(int X=0;X<N;X++)
#define REP2(X,L,R) for(int X=L;X<=R;X++)
#define DEP(X,R,L) for(int X=R;X>=L;X--)
#define CLR(A,X) memset(A,X,sizeof(A))
#define IT iterator
typedef long long ll;
typedef pair<int,int> PII;
typedef vector<PII> VII;
typedef vector<int> VI;
#define MAXN 1000010
int a[MAXN];
int main()
{
    int n;
    while(scanf("%d",&n)&&n){
         a[1]=3;
         a[2]=1;
         for(int i=3;i<=n;i++){
             if(i&1)a[i]=i+2;
             else a[i]=i-2;
         }
         if(n&1)a[n]=n-1;
         else{
             a[n]=n-2;
             a[n-1]=n;
         }
         printf("%d",a[1]);
         for(int i=2;i<=n;i++){
             printf(" %d",a[i]);
         }
         printf("
");
    }
    return 0;
}