From a6c97b96b6bd85073db0e3b5fce337751fe9d5a7 Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Fri, 26 Sep 2025 23:47:52 +0900
Subject: [PATCH] 20250926 baekjoon

---
 code_study/Baekjoon/python/31868.py  |  2 ++
 code_study/Baekjoon/swift/1967.swift | 53 ++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 code_study/Baekjoon/python/31868.py
 create mode 100644 code_study/Baekjoon/swift/1967.swift

diff --git a/code_study/Baekjoon/python/31868.py b/code_study/Baekjoon/python/31868.py
new file mode 100644
index 0000000..179e946
--- /dev/null
+++ b/code_study/Baekjoon/python/31868.py
@@ -0,0 +1,2 @@
+N, K = map(int, input().split())
+print(K//(2**(N-1)))
diff --git a/code_study/Baekjoon/swift/1967.swift b/code_study/Baekjoon/swift/1967.swift
new file mode 100644
index 0000000..bc11e6e
--- /dev/null
+++ b/code_study/Baekjoon/swift/1967.swift
@@ -0,0 +1,53 @@
+func findNode(from start: Int, of graph: [[(node: Int, weight: Int)]]) -> (node: Int, length: Int) {
+    var result = (node: start, length: 0)
+    
+    var visited = Array(repeating: false, count: graph.count)
+    var stack = [(node: Int, length: Int)]()
+    stack.append(result)
+    visited[start] = true
+    
+    while !stack.isEmpty {
+        if let (now, cur_len) = stack.popLast()
+        {
+            if cur_len > result.length {
+                result = (node: now, length: cur_len)
+            }
+            
+            for next in graph[now] {
+                if !visited[next.node] {
+                    visited[next.node] = true
+                    stack.append((node: next.node, length: cur_len + next.weight))
+                }
+            }
+        }
+    }
+    
+    return result
+}
+
+if let N = Int(readLine() ?? "0")
+{
+    if N == 1 {
+        print(0)
+    }
+    else {
+        var graph = Array(repeating: [(node: Int, weight: Int)](), count: N+1)
+        
+        for _ in 0..<N-1 {
+            if let line = readLine(),
+               let data = line.split(separator: " ").compactMap({Int($0)}) as? [Int],
+               data.count == 3
+            {
+                let parent = data[0]
+                let child = data[1]
+                let weight = data[2]
+                
+                graph[parent].append((node: child, weight: weight))
+                graph[child].append((node: parent, weight: weight))
+            }
+        }
+        
+        let startNode: Int = findNode(from: 1, of: graph).node
+        print(findNode(from: startNode, of: graph).length)
+    }
+}