백준 1967번 트리의 지름

문제 링크: https://www.acmicpc.net/problem/1967

Author: skysign

백준 1967번 트리의 지름/main.py

@@ -0,0 +1,39 @@
+import sys
+sys.setrecursionlimit(11000)
+from collections import defaultdict
+
+
+def solve():
+    n = int(sys.stdin.readline().strip())
+    edges = defaultdict(list)
+
+    for _ in range(n - 1):
+        parent, child, length = map(int, sys.stdin.readline().strip().split(' '))
+        edges[parent].append([child, length])
+
+    answer = [0]
+    dfs(1, answer, edges)
+
+    print(answer[0])
+
+
+def dfs(parent, answer, edges):
+    local_answers = []
+
+    for child, length in edges[parent]:
+        local_answers.append(length + dfs(child, answer, edges))
+
+    if len(local_answers) >= 2:
+        local_answers.sort(reverse=True)
+        local_answer = sum(local_answers[:2])
+        answer[0] = max(answer[0], local_answer)
+
+    if len(local_answers) >= 1:
+        answer[0] = max(answer[0], local_answers[0])
+        return local_answers[0]
+
+    return 0
+
+
+if __name__ == '__main__':
+    solve()

백준 1967번 트리의 지름/test1.txt

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+12
+1 2 3
+1 3 2
+2 4 5
+3 5 11
+3 6 9
+4 7 1
+4 8 7
+5 9 15
+5 10 4
+6 11 6
+6 12 10

백준 1967번 트리의 지름/test1_answer.txt

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+45

백준 1967번 트리의 지름/test_main.py

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+import sys
+from pathlib import Path
+from unittest import TestCase
+from main import solve
+
+
+class Test(TestCase):
+    def my_solve(self, testcase_input):
+        sys.stdin = open(testcase_input, 'r')
+        stdout = sys.stdout
+        sys.stdout = open('stdout.txt', 'w')
+        solve()
+        sys.stdout.close()
+        sys.stdout = stdout
+
+    def test_solve(self, testcase_number: str):
+        self.my_solve('test' + testcase_number + '.txt')
+        self.assertEqual(
+            Path('test' + testcase_number + '_answer.txt').read_text().strip(),
+            Path('stdout.txt').read_text().strip())
+
+    def test1_solve(self):
+        self.test_solve('1')