[1231] 13913번 - 숨바꼭질 4

src/Problem13913.java

@@ -0,0 +1,76 @@
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+import java.util.Queue;
+import java.util.LinkedList;
+import java.util.Stack;
+import java.lang.StringBuilder;
+
+public class Problem13913 {
+    static final int MAX = 100000;
+    static int[] before = new int[MAX + 1];
+    static int[] count = new int[MAX + 1];
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+
+
+    public static void main(String[] args) throws IOException{
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        int n = Integer.parseInt(st.nextToken());
+        int k = Integer.parseInt(st.nextToken());
+
+        Arrays.fill(count, MAX+1);
+        Arrays.fill(before, 0);
+
+        Queue<Integer> queue = new LinkedList<>();
+        queue.add(n);
+
+        before[n] = -1;
+        count[n] = 0;
+
+        while(!queue.isEmpty()){
+            int cur = queue.poll();
+
+            if (cur == k) {
+                writePath(n, k);
+                return;
+            }
+
+            int[] nextPositions = {cur - 1, cur + 1, cur * 2};
+
+            for (int next : nextPositions) {
+                if (next >= 0 && next <= MAX && count[next] > count[cur] + 1) {
+                    before[next] = cur;
+                    count[next] = count[cur] + 1;
+                    queue.add(next);
+                }
+            }
+        }
+
+    }
+
+    public static void writePath(int n, int k) throws IOException {
+        Stack<Integer> stack = new Stack<>();
+        int index = k;
+        while (index != n) {
+            stack.push(index);
+            index = before[index];
+        }
+
+        stack.push(n);
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(count[k]).append("\n");
+        while (!stack.isEmpty()) {
+            sb.append(stack.pop()).append(" ");
+        }
+        bw.write(sb.toString());
+        bw.flush();
+        bw.close();
+    }
+}