CodeForces - 515C Drazil and Factorial

题目：

Description

Drazil is playing a math game with Varda.

Let's define  for positive integer x as a product of factorials of its digits. For example, .

First, they choose a decimal number a consisting of n digits that contains at least one digit larger than 1. This number may possibly start with leading zeroes. Then they should find maximum positive number x satisfying following two conditions:

1. x doesn't contain neither digit 0 nor digit 1.

2.  = .

Help friends find such number.

Input

The first line contains an integer n (1 ≤ n ≤ 15) — the number of digits in a.

The second line contains n digits of a. There is at least one digit in a that is larger than 1. Number a may possibly contain leading zeroes.

Output

Output a maximum possible integer satisfying the conditions above. There should be no zeroes and ones in this number decimal representation.

Sample Input

Input

4
1234

Output

33222

Input

3
555

Output

555

这个题目其实就是全部替换成2/3/5/7，然后按照从大到小的顺序全部输出即可

代码：

#include<iostream>
using namespace std;

int main()
{
	int n;
	cin >> n;
	char c;
	int n2 = 0, n3 = 0, n5 = 0, n7 = 0;
	while (n--)
	{
		cin >> c;
		if (c == '2')n2++;
		if (c == '3')n3++;
		if (c == '4')
		{
			n3++;
			n2 += 2;
		}
		if (c == '5')n5++;
		if (c == '6')
		{
			n3++;
			n5++;
		}
		if (c == '7')n7++;
		if (c == '8')
		{
			n7++;
			n2 += 3;
		}
		if (c == '9')
		{
			n7++;
			n2++;
			n3 += 2;
		}
	}
	while (n7--)cout << '7';
	while (n5--)cout << '5';
	while (n3--)cout << '3';
	while (n2--)cout << '2';
	cout << endl;
	return 0;
}

为什么是2/3/5/7呢，因为它们是素数。

也就是说，5的倍数的最小阶乘就是5！等等。。