From 6855b045dc6f1a14d2fe600c4e02c5f2cc13f6f4 Mon Sep 17 00:00:00 2001
From: tgyuuAn <atg0614@gmail.com>
Date: Sun, 25 Aug 2024 14:48:54 +0900
Subject: [PATCH] 2024-08-23

---
 ...0 \353\247\210\353\213\210\354\225\204.py" | 31 +++++++++++++++++++
 tgyuuAn/README.md                             |  1 +
 2 files changed, 32 insertions(+)
 create mode 100644 "tgyuuAn/DFS/\353\223\261\354\202\260 \353\247\210\353\213\210\354\225\204.py"

diff --git "a/tgyuuAn/DFS/\353\223\261\354\202\260 \353\247\210\353\213\210\354\225\204.py" "b/tgyuuAn/DFS/\353\223\261\354\202\260 \353\247\210\353\213\210\354\225\204.py"
new file mode 100644
index 00000000..7af2aa8f
--- /dev/null
+++ "b/tgyuuAn/DFS/\353\223\261\354\202\260 \353\247\210\353\213\210\354\225\204.py"	
@@ -0,0 +1,31 @@
+import sys
+sys.setrecursionlimit(10 ** 6)
+
+def input(): return sys.stdin.readline().rstrip()
+
+N = int(input())
+# N = 30 만 -> O(N*log(N))
+
+tree = [[] for _ in range(N+1)]
+for _ in range(N-1):
+    node1, node2 = map(int, input().split())
+    tree[node1].append(node2)
+    tree[node2].append(node1)
+
+answer = 0
+def dfs(now_idx, visited, tree):
+    global answer
+    
+    temp_cnt = 1
+    for next_node in tree[now_idx]:
+        if next_node in visited: continue
+        visited.add(next_node)
+        temp = dfs(next_node, visited, tree)
+        answer += temp * (temp-1) // 2
+        answer += temp * (N-temp)
+        temp_cnt += temp
+
+    return temp_cnt
+
+dfs(1,{1,}, tree)
+print(answer)    
diff --git a/tgyuuAn/README.md b/tgyuuAn/README.md
index 73034d56..dfd14f36 100644
--- a/tgyuuAn/README.md
+++ b/tgyuuAn/README.md
@@ -77,4 +77,5 @@
 | 68차시 | 2024.08.06 |  그리디  | <a href="https://www.acmicpc.net/problem/24337">가희와 탑</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/226
 | 69차시 | 2024.08.10 |  누적합, 수학  | <a href="https://www.acmicpc.net/problem/9527">1의 개수 세기</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/228
 | 70차시 | 2024.08.16 |  스택  | <a href="https://www.acmicpc.net/problem/22866">탑 보기</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/232
+| 72차시 | 2024.08.23 |  DFS + 트리  | <a href="https://www.acmicpc.net/problem/20188">등산 마니아</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/238
 ---