CF 305A(Strange Addition贪心+分类讨论)

Unfortunately, Vasya can only sum pairs of integers (a, b), such that for any decimal place at least one number has digit 0 in this place. For example, Vasya can sum numbers 505 and 50, but he cannot sum 1 and 4.

Vasya has a set of k distinct non-negative integers d₁, d₂, ..., d_k.

Vasya wants to choose some integers from this set so that he could sum any two chosen numbers. What maximal number of integers can he choose in the required manner?

Input

The first input line contains integer k (1 ≤ k ≤ 100) — the number of integers.

The second line contains k distinct space-separated integers d₁, d₂, ..., d_k (0 ≤ d_i ≤ 100).

Output

In the first line print a single integer n the maximum number of the chosen integers. In the second line print n distinct non-negative integers — the required integers.

If there are multiple solutions, print any of them. You can print the numbers in any order.

Sample test(s)
input
4
100 10 1 0
output
4
0 1 10 100 
input
3
2 70 3
output
2
2 70  
 
        

所有数都不同。

0和100显然取。

接下来可以取个位+十位 or 个,十位

分类讨论即可

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<functional>
#include<cmath>
#include<cctype>
using namespace std;
#define For(i,n) for(int i=1;i<=n;i++)
#define Rep(i,n) for(int i=0;i<n;i++)
#define Fork(i,k,n) for(int i=k;i<=n;i++)
#define ForD(i,n) for(int i=n;i;i--)
#define Forp(x) for(int p=pre[x];p;p=next[p])
#define RepD(i,n) for(int i=n;i>=0;i--)
#define MAXN (100+10)
int n,ans[MAXN],size=0;
bool b1=0,b2=0;
int main()
{
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	scanf("%d",&n);
	int p=0;
	For(i,n)
	{
		int a;
		scanf("%d",&a);
		if (!a||a==100) ans[++size]=a;
		else if (a<10&&!b1) b1=1,ans[++size]=a;
		else if (!(a%10)&&!b2) b2=1,ans[++size]=a;
		else p=a;
	}	
	if (!b1&&!b2&&p) ans[++size]=p;
	cout<<size<<endl;
	For(i,size-1) cout<<ans[i]<<' ';cout<<ans[size]<<endl; 
	
	return 0;
}