[BOJ] #2644. 촌수계산 / 실버2 / 30분 / 성공

Author: Mingguriguri

minjeong/DFSBFS/2025-08-04-[백준]-#2644-촌수계산.py

@@ -0,0 +1,31 @@
+import sys
+input = sys.stdin.readline
+
+def dfs(start, cnt):
+    global chonsu
+    if start == y:
+        chonsu = cnt
+        return
+
+    for i in graph[start]:
+        if not visited[i]:
+            visited[i] = True
+            dfs(i, cnt + 1)
+            visited[i] = False
+
+
+n = int(input()) # 전체 사람 개수
+x, y = map(int, input().split())
+graph = [[] for _ in range(n+1)]
+visited = [False for _ in range(n + 1)]
+chonsu = -1 # 정답으로 반환할 촌수
+
+m = int(input()) # 부모 자식들간의 관계 개수
+for _ in range(m):
+    a, b = map(int, input().split())
+    graph[a].append(b)
+    graph[b].append(a)
+
+visited[x] = True
+dfs(x, 0)
+print(chonsu)