CF 502 C- The Phone Number(思维)

Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number!

The only thing Mrs. Smith remembered was that any permutation of nn can be a secret phone number. Only those permutations that minimize secret value might be the phone of her husband.

The sequence of nn integers is called a permutation if it contains all integers from 11 to nn exactly once.

The secret value of a phone number is defined as the sum of the length of the longest increasing subsequence (LIS) and length of the longest decreasing subsequence (LDS).

A subsequence ai1,ai2,…,aikai1,ai2,…,aik where 1≤i1<i2<…<ik≤n1≤i1<i2<…<ik≤n is called increasing if ai1<ai2<ai3<…<aikai1<ai2<ai3<…<aik. If ai1>ai2>ai3>…>aikai1>ai2>ai3>…>aik, a subsequence is called decreasing. An increasing/decreasing subsequence is called longest if it has maximum length among all increasing/decreasing subsequences.

For example, if there is a permutation [6,4,1,7,2,3,5], LIS of this permutation will be [1,2,3,5], so the length of LIS is equal to 44. LDScan be [6,4,1], [6,4,2], or [6,4,3], so the length of LDS is 33.

Note, the lengths of LIS and LDS can be different.

So please help Mrs. Smith to find a permutation that gives a minimum sum of lengths of LIS and LDS.

Input

The only line contains one integer nn (1≤n≤10^5 1≤n≤10^5) — the length of permutation that you need to build.

Output

Print a permutation that gives a minimum sum of lengths of LIS and LDS.

If there are multiple answers, print any.

Examples

input

4

output

3 4 1 2

input

2

output

2 1

Note

In the first sample, you can build a permutation [3,4,1,2]. LIS is [3,4] (or [1,2]), so the length of LIS is equal to 22. LDS can be ony of [3,1], [4,2], [3,2], or [4,1]. The length of LDS is also equal to 2. The sum is equal to 4. Note that [3,4,1,2] is not the only permutation that is valid.

In the second sample, you can build a permutation [2,1]. LIS is [1] (or [2]), so the length of LIS is equal to 1. LDS is [2,1], so the length of LDS is equal to 2. The sum is equal to 3. Note that permutation [1,2] is also valid.

题目大意:给出一个n,输出1-n的全排列中最长上升子序列+最长下降子序列和最小的方案

思路:完全没有往数学方面想,,,,看大佬们的代码才明白怎么回事,观察样例,发现它是以对半输出的,大胆试一发:过8个点(这也能过8个点......),这也算是向ac靠近了一点点。要求只输出一种满足的情况就行,那上升下降子序列都按顺序好了,然后问题转化为类似矩形求面积(例如16,对半8+8,开根号4+4),在面积一定的时候,周长最小的是正方形 。

代码如下:

#include <iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<algorithm>
int n,mid,flag,l;
using namespace std;
int t1;
int main() 
{
    while(~scanf("%d",&n))
    {
        t1=0 ;
        l=(int)sqrt(n);
        for(int i=n-l+1;i>=1;i-=l)
        {
            for(int j=0;j<=l-1;j++)
            {
                cout<<i+j;
                    t1++;
                    if(t1!=n) cout <<" ";
            }
        }
        if(n%l!=0)
        {
            for(int i=1;i<=n%l;i++)
            {
                cout<<i;
                if(i!=n%l) cout<<" ";
            }
        }
        cout<<endl;
    }
    return 0;
}

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转载自blog.csdn.net/PleasantlY1/article/details/81531808
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