From f45b13256cf3fa5f70fc0e7e2409067e9ba4c6ff Mon Sep 17 00:00:00 2001
From: Won Joon Thomas Choi <113500771+724thomas@users.noreply.github.com>
Date: Sat, 5 Sep 2026 23:53:44 +0900
Subject: [PATCH] Create 851. Loud and Rich.py

---
 .../851. Loud and Rich.py"                    | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 "leetcode3/\354\265\234\354\233\220\354\244\200/851. Loud and Rich.py"

diff --git "a/leetcode3/\354\265\234\354\233\220\354\244\200/851. Loud and Rich.py" "b/leetcode3/\354\265\234\354\233\220\354\244\200/851. Loud and Rich.py"
new file mode 100644
index 00000000..306ed440
--- /dev/null
+++ "b/leetcode3/\354\265\234\354\233\220\354\244\200/851. Loud and Rich.py"	
@@ -0,0 +1,31 @@
+class Solution:
+    def loudAndRich(self, richer: List[List[int]], quiet: List[int]) -> List[int]:
+        n = len(quiet)
+
+        graph = [[] for _ in range(n)]
+
+        for rich, poor in richer:
+            graph[poor].append(rich)
+
+        answer = [-1] * n
+
+        def dfs(x):
+            # 이미 계산했다면 재사용
+            if answer[x] != -1:
+                return answer[x]
+
+            # 자기 자신도 후보
+            answer[x] = x
+
+            for rich in graph[x]:
+                candidate = dfs(rich)
+
+                if quiet[candidate] < quiet[answer[x]]:
+                    answer[x] = candidate
+
+            return answer[x]
+
+        for i in range(n):
+            dfs(i)
+
+        return answer