[Week08] BOJ 13549: 숨바꼭질 3

weekly/week08/BOJ_13549_숨바꼭질3/whqtker.java

@@ -0,0 +1,54 @@
+package boj.boj_13549;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayDeque;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+public class Main {
+
+    static final int LIMIT = 1000001;
+
+    public static void main(String[] args) throws IOException {
+        // 위치를 노드, 걸린 시간을 간선으로 간주하면 BFS로 풀 수 있다. 최간 시간을 구하는 것이기 때문.
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb = new StringBuilder();
+
+        int n, k;
+        String line = br.readLine();
+        StringTokenizer st = new StringTokenizer(line);
+        n = Integer.parseInt(st.nextToken());
+        k = Integer.parseInt(st.nextToken());
+
+        int[] visited = new int[LIMIT];
+        Queue<Integer> q = new ArrayDeque<>();
+        visited[n] = 1;
+        q.offer(n);
+
+        while (!q.isEmpty()) {
+            int x = q.poll();
+
+            if (x == k) break;
+
+            if (2 * x < LIMIT && visited[2 * x] == 0) {
+                visited[2 * x] = visited[x];
+                q.offer(2 * x);
+            }
+
+            if (x - 1 >= 0 && visited[x - 1] == 0) {
+                visited[x - 1] = visited[x] + 1;
+                q.offer(x - 1);
+            }
+
+            if (x + 1 < LIMIT && visited[x + 1] == 0) {
+                visited[x + 1] = visited[x] + 1;
+                q.offer(x + 1);
+            }
+        }
+
+        sb.append(visited[k] - 1);
+        System.out.println(sb);
+    }
+}