[BOJ] 촌수계산 / 실버2 / 40분

https://www.acmicpc.net/problem/2644

Author: YoonYn9915

YoonYn9915/Graph/2024-09-30-[백준]-#2644-촌수계산.py

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+
+N = int(input())
+A, B = map(int, input().split())
+M = int(input())
+graph = [[] for _ in range(N+1)]
+visited = [False] * (N+1)
+result = []
+
+for _ in range(M):
+  x, y = map(int, input().split())
+  graph[x].append(y)
+  graph[y].append(x)
+
+# dfs
+def dfs(v, num):
+  num += 1
+  visited[v] = True
+
+  if v == B:
+    result.append(num)
+
+  for i in graph[v]:
+    if not visited[i]:
+      dfs(i, num)
+
+dfs(A, 0)
+if len(result) == 0:
+  print(-1)
+else:
+  print(result[0]-1)