题解 | 小红的数位删除

import java.util.*;
import java.io.*;

public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }

    public static void main(String[] args) {
        FastReader sc = new FastReader();
        int a = sc.nextInt();
        int b = sc.nextInt();
        int m = String.valueOf(a).length();
        int n = String.valueOf(b).length();
        List<String> tmpA = cal(a);
        List<String> tmpB = cal(b);
        int res = 100;
        for(String p: tmpA){
            // System.out.print(p + " p ");
            int x = Integer.valueOf(p);
            int curLenX = p.length();
            for(String q: tmpB){
                // System.out.print(q + " q ");
                int y = Integer.valueOf(q);
                int curLenY = q.length();
                if(x==0 || y == 0){
                    res = Math.min(res, m-curLenX+n-curLenY);
                }else if(x%y==0 || y%x==0){
                    res = Math.min(res, m-curLenX+n-curLenY);
                }
            }
        }
        if(res == 100){
            System.out.println(-1);
            return ;
        }
        System.out.println(res);
    }

    public static List<String> cal(int num) {
        String s = String.valueOf(num);
        int n = s.length();
        List<String> res = new ArrayList<>();
        for (int i = 1; i < (1 << n); i++) {
            StringBuilder ans = new StringBuilder();
            for (int j = 0; j < n; j++) {
                if ((i & (1 << j)) != 0) {
                    ans.append(s.charAt(j) + "");
                }
            }
            if(!ans.toString().equals("")){
                res.add(ans.toString());
            }
        }
        return res;
    }
}