From 6eb2f1ca93226934e645f64cd5ce11567f331929 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EC=97=BC=ED=98=9C=EC=A0=95?=
 <122238744+cyzlcyzl@users.noreply.github.com>
Date: Sat, 5 Sep 2026 23:52:12 +0900
Subject: [PATCH] Create 851. Loud and Rich.java

---
 .../851. Loud and Rich.java"                  | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 "leetcode3/\354\227\274\355\230\234\354\240\225/851. Loud and Rich.java"

diff --git "a/leetcode3/\354\227\274\355\230\234\354\240\225/851. Loud and Rich.java" "b/leetcode3/\354\227\274\355\230\234\354\240\225/851. Loud and Rich.java"
new file mode 100644
index 00000000..422401fa
--- /dev/null
+++ "b/leetcode3/\354\227\274\355\230\234\354\240\225/851. Loud and Rich.java"	
@@ -0,0 +1,39 @@
+class Solution {
+    public int[] loudAndRich(int[][] richer, int[] quiet) {
+        int n = quiet.length;
+        List<List<Integer>> graph = new ArrayList<>();
+        for (int i = 0; i < n; i++) {
+            graph.add(new ArrayList<>());
+        }
+        // richer[i] = [a, b] : a는 b보다 부자 -> b는 a에게 정보를 받을 수 있음
+        for (int[] r : richer) {
+            graph.get(r[1]).add(r[0]);
+        }
+
+        int[] answer = new int[n];
+        Arrays.fill(answer, -1);
+
+        for (int i = 0; i < n; i++) {
+            dfs(i, graph, quiet, answer);
+        }
+
+        return answer;
+    }
+
+    private int dfs(int person, List<List<Integer>> graph, int[] quiet, int[] answer) {
+        if (answer[person] != -1) {
+            return answer[person];
+        }
+
+        answer[person] = person; // 자기 자신이 일단 후보
+
+        for (int richerPerson : graph.get(person)) {
+            int candidate = dfs(richerPerson, graph, quiet, answer);
+            if (quiet[candidate] < quiet[answer[person]]) {
+                answer[person] = candidate;
+            }
+        }
+
+        return answer[person];
+    }
+}