[Link] https://www.acmicpc.net/problem/13913
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import java.util.*;
import java.io.*;
public class Main {
static BufferedReader br;
static int max = 0, maxIdx = 0;
public static void main(String[] args) throws IOException {
br = new BufferedReader(new InputStreamReader(System.in));
StringBuilder sb = new StringBuilder();
String[] line = getLine();
int n = toi(line[0]), k = toi(line[1]), range = 100001;
if(n == k) {
println("0");
print(n);
return;
}
int[] dp = new int[range];
ArrayList<Integer> al = new ArrayList<>();
int time = 0;
dp[n] = -1;
al.add(n);
loop:
for(int i = 0; i < range; i++) {
ArrayList<Integer>temp = new ArrayList<>();
for(int e: al) {
if(e == k) {
time = i;
break loop;
}
if(e > 0 && dp[e - 1] == 0) {
temp.add(e-1);
dp[e-1] = i + 1;
}
if(e > k) continue;
if(e < range - 2 && dp[e + 1] == 0) {
temp.add(e+1);
dp[e+1] = i + 1;
}
if(2 * e <= range - 1 && dp[2 * e] == 0) {
temp.add(2*e);
dp[2*e] = i + 1;
}
}
al = temp;
}
println(time);
Stack<Integer> stack = new Stack<>();
stack.push(k);
int idx = k, val = time;
while(val != 1) {
if(idx + 1 < range && dp[idx + 1] == val - 1) {
idx++;
val--;
stack.add(idx);
continue;
}
if(idx > 0 && dp[idx - 1] == val - 1) {
idx--;
val--;
stack.add(idx);
continue;
}
if((idx&1) == 0 && dp[idx/2] == val - 1) {
idx/=2;
val--;
stack.add(idx);
}
}
stack.add(n);
while(!stack.isEmpty()) sb.append(stack.pop()).append(" ");
sb.append("\n");
// for(int e: stack) sb.append(dp[e]).append(" ");
print(sb);
}
static int toi(String s) { return Integer.parseInt(s); }
static String[] getLine() throws IOException { return br.readLine().split(" "); }
static <T> void print(T s) { System.out.print(s); }
static <T> void println(T s) { System.out.println(s); }
}