Divide by three, multiply by two CodeForces - 977D(思维+map)

本文介绍了一个特定条件下的数列排序算法,目标是将一个包含特定数学操作(乘以2或除以3)的数列重新排序,使得每个元素都是前一个元素的两倍或三分之一。该算法首先找到数列中的最小值作为起点,然后通过递归地查找可乘以2或可被3整除的数来构建排序后的数列。

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D. Divide by three, multiply by two
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Polycarp likes to play with numbers. He takes some integer number xx, writes it down on the board, and then performs with it n1n−1operations of the two kinds:

  • divide the number xx by 33 (xx must be divisible by 33);
  • multiply the number xx by 22.

After each operation, Polycarp writes down the result on the board and replaces xx by the result. So there will be nn numbers on the board after all.

You are given a sequence of length nn — the numbers that Polycarp wrote down. This sequence is given in arbitrary order, i.e. the order of the sequence can mismatch the order of the numbers written on the board.

Your problem is to rearrange (reorder) elements of this sequence in such a way that it can match possible Polycarp's game in the order of the numbers written on the board. I.e. each next number will be exactly two times of the previous number or exactly one third of previous number.

It is guaranteed that the answer exists.

Input

The first line of the input contatins an integer number nn (2n1002≤n≤100) — the number of the elements in the sequence. The second line of the input contains nn integer numbers a1,a2,,ana1,a2,…,an (1ai310181≤ai≤3⋅1018) — rearranged (reordered) sequence that Polycarp can wrote down on the board.

Output

Print nn integer numbers — rearranged (reordered) input sequence that can be the sequence that Polycarp could write down on the board.

It is guaranteed that the answer exists.

Examples
input
Copy
6
4 8 6 3 12 9
output
Copy
9 3 6 12 4 8 
input
Copy
4
42 28 84 126
output
Copy
126 42 84 28 
input
Copy
2
1000000000000000000 3000000000000000000
output
Copy
3000000000000000000 1000000000000000000 
Note

In the first example the given sequence can be rearranged in the following way: [9,3,6,12,4,8][9,3,6,12,4,8]. It can match possible Polycarp's game which started with x=9x=9


题意:给出一串长为n的数列,现给出一个排序方案 ai是ai+1的3倍或者ai+1是ai的2倍,保证给出的数列一定可以排序。


思路:因为最小值只有一种方案,所以现找出最小值,然后由最小值向两边加点就可以了(这里用map来判断一个数是否是给出的数列中的数)


#include "iostream"
#include "algorithm"
#include "map"
using namespace std;
typedef long long ll;
ll ans[205],Min=1e19,a;
map<ll,bool> mp;
int main()
{
    ios::sync_with_stdio(false);
    mp.clear();
    int n,t=1,l,r;
    cin>>n;
    for(int i=0;i<n;i++){cin>>a;mp[a]=1;Min=min(Min,a);}
    l=r=100;//有中间向两边加点
    ans[100]=Min;
    while(1){//向左边加点
        if(mp[ans[l]*3]) l--,ans[l]=ans[l+1]*3;
        else if(ans[l]%2==0&&mp[ans[l]/2]) l--,ans[l]=ans[l+1]/2;
        else break;
    }
    while(1&&r-l<n){//向右边加点
        if(mp[ans[r]*2]) r++,ans[r]=ans[r-1]*2;
        else if(ans[r]%3==0&&mp[ans[r]/3]) r++,ans[r]=ans[r-1]/3;
        else break;
    }
    for(int i=l;i<=r;i++){
        cout<<ans[i];
        if(i!=r)
            cout<<" ";
        else
            cout<<endl;
    }
    return 0;
}

1. Problem Description: A complex number is a number of the form a +bi, where a and b are real numbers and i is √-1 The numbers a and b are known as the real part and imaginary part of the complex number, respectively. You can perform addition, subtraction, multiplication, and division for complex numbers using the following formula: a+bi+c+di=(a+c)+(b+d)i a+bi-(c+di)=(a-c)+(b-d)i 第2页共2页 (a+bi)*(c+di)=(ac-bd)+(bc+ad)i (a+bi)/c+di)=(ac+bd)/c²+)+(bc-ad)i/(+) You can also obtain the absolute value for a complex number using the following formula: latbil=√a²+b (A complex number can be interpreted as a point on a plane by identifying the (a, b) values as the coordinates of the point. The absolute value of the complex number corresponds to the distance of the point to the origin, as shown in Figure 13.12b.) Design a class named Complex for representing complex numbers and the methods add, subtract, multiply, divide, abs for performing complex-number operations, and override toString method for returning a string representation for a complex number. The toString method returns a + bi as a string. If b is 0, it simply returns a. Provide three constructors Complex(a, b), Complex(a), and Complex(). Complex() creates a Complex object for number 0 and Complex(a) creates a Complex object with 0 for b. Also provide the getRealPart() and getlmaginaryPart() methods for returning the real and imaginary part of the complex number, respectively. Your Complex class should also implement the Cloneable interface. Write a test program that prompts the user to enter two complex numbers and display the result of their addition, subtraction, multiplication, and division. Here is a sample run: <Output> Enter the first complex number: 3.5 5.5 Enter the second complex number:-3.5 1 (3.5 + 5.5i) +(-3.5 + 1.0i)= 0.0 + 6.5 (3.5 + 5.5i)-(-3.5 + 1.0i)= 7.0 + 4.5i (3.5 + 5.5i)*(-3.5 + 1.0i) =-17.75 +-15.75i (3.5 + 5.5i) /(-3.5 + 1.0i)=-0.5094 +-1.7i |3.5 + 5.5il = 6.519202405202649 <End Output>
最新发布
06-09
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