Problem:
Score : 400 points

Problem Statement

Find the largest integer that can be formed with exactly N matchsticks, under the following conditions:

Every digit in the integer must be one of the digits A_1, A_2, ..., A_M (1 \leq A_i \leq 9).

The number of matchsticks used to form digits 1, 2, 3, 4, 5, 6, 7, 8, 9 should be 2, 5, 5, 4, 5, 6, 3, 7, 6, respectively.

Constraints

All values in input are integers.

2 \leq N \leq 10^4

1 \leq M \leq 9

1 \leq A_i \leq 9

A_i are all different.

There exists an integer that can be formed by exactly N matchsticks under the conditions.

Input

Input is given from Standard Input in the following format:

N M
A_1 A_2 ... A_M

Output

Print the largest integer that can be formed with exactly N matchsticks under the conditions in the problem statement.

Sample Input 1

20 4
3 7 8 4

Sample Output 1

777773

The integer 777773 can be formed with 3 + 3 + 3 + 3 + 3 + 5 = 20 matchsticks, and this is the largest integer that can be formed by 20 matchsticks under the conditions.

Sample Input 2

101 9
9 8 7 6 5 4 3 2 1

Sample Output 2

71111111111111111111111111111111111111111111111111

The output may not fit into a 64-bit integer type.

Sample Input 3

15 3
5 4 6

Sample Output 3

654

Solution in Rust (1.15.1) (judge verdict: Wrong Answer)

use std::str::FromStr;
use std::fmt::Debug;

fn read_as_vec<T>() -> Vec<T>
where T: FromStr, <T as FromStr>::Err : Debug{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().split_whitespace().map(|c| T::from_str(c).unwrap()).collect()

}

fn read_as_string() -> String{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main(){
    let line: Vec<usize> = read_as_vec();
    let (n, m) = (line[0], line[1]);
    let kinds: Vec<usize> = read_as_vec();
    //println!("kinds= {:?}", kinds);
    //                           0, 1, 2, 3, 4, 5, 6, 7, 8, 9
    let costs: Vec<usize> = vec![0, 2, 5, 5, 4, 5, 6, 3, 7, 6];
    let mut cost_ints: Vec<(usize, usize)> = Vec::new();

    for kind in &kinds{
        //cost_ints.push((costs[*kind], *kind));
        cost_ints.push((*kind, costs[*kind]));
    }

    cost_ints.sort();
    cost_ints.reverse();
    //println!("cost_int = {:?}", cost_ints);
    //solve the number of digits
    let mut dp = vec![0 as i32;n+1];

    for i in 2..n+1{
        for kind in &kinds{
            if costs[*kind] <= i &&dp[i]-1 < dp[i - costs[*kind]]{
                dp[i] = dp[i - costs[*kind]]+1;
            }
        }
    }

    let num_digits = dp[n];
    //println!("num_digits = {}", num_digits);
    let mut n = n;
    for _ in 0..num_digits{
        for cost_int in &cost_ints{
            if n < 2{
                break;
            }
            if n < (*cost_int).1{
                continue;
            }
            if dp[n - (*cost_int).1] == dp[n] - 1 && (dp[n - (*cost_int).1] != 0 || n - cost_int.1 == 0){
                print!("{}", cost_int.0);
                n -= (*cost_int).1;
                break;
            }
        }
        
    }
    println!("");
}