From 85e556790de8a9f1d967556b2c293664e4ddae79 Mon Sep 17 00:00:00 2001
From: kimsejeong <clean01@hanyang.ac.kr>
Date: Tue, 20 Feb 2024 01:13:35 +0900
Subject: [PATCH] [week-05-dp] 25215, 2533

---
 week05-dp/clean2001/.gitkeep    |  0
 week05-dp/clean2001/B25215.java | 34 ++++++++++++++++++++++++
 week05-dp/clean2001/B2533.java  | 46 +++++++++++++++++++++++++++++++++
 3 files changed, 80 insertions(+)
 delete mode 100644 week05-dp/clean2001/.gitkeep
 create mode 100644 week05-dp/clean2001/B25215.java
 create mode 100644 week05-dp/clean2001/B2533.java

diff --git a/week05-dp/clean2001/.gitkeep b/week05-dp/clean2001/.gitkeep
deleted file mode 100644
index e69de29..0000000
diff --git a/week05-dp/clean2001/B25215.java b/week05-dp/clean2001/B25215.java
new file mode 100644
index 0000000..d9359f6
--- /dev/null
+++ b/week05-dp/clean2001/B25215.java
@@ -0,0 +1,34 @@
+// 백준 25215. 타이핑 
+import java.io.*;
+import java.util.*;
+
+class B25215 {
+    static String s;
+    static int dp[][];
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        s = br.readLine().trim();
+        dp = new int[2][s.length()+1];
+
+        s = " " + s; // 인덱스를 맞춰주기 위해 (문자열의 시작을 1부터)
+
+        dp[0][0] = 0; // 0행 -> 마름모 비활성화
+        dp[1][0] = 1; // 1행 -> 마름모 활성화
+
+        for(int i=1; i<s.length(); ++i) {
+            if(s.charAt(i) >= 'a' && s.charAt(i) <= 'z') { // 소문자이면
+                dp[0][i] = Math.min(dp[0][i-1] + 1, dp[1][i-1]+2);
+                dp[1][i] = dp[1][i-1] + 2; // 활성화를 유지
+            } else { // 대문자이면
+                dp[1][i] = Math.min(dp[1][i-1] + 1, dp[0][i-1]+2);
+                dp[0][i] = dp[0][i-1] + 2; // 비활유지
+            }
+        }
+
+        int ans = Math.min(dp[0][s.length()-1], dp[1][s.length()-1]);
+
+        System.out.println(ans);
+    }
+
+}
\ No newline at end of file
diff --git a/week05-dp/clean2001/B2533.java b/week05-dp/clean2001/B2533.java
new file mode 100644
index 0000000..3464f64
--- /dev/null
+++ b/week05-dp/clean2001/B2533.java
@@ -0,0 +1,46 @@
+// 2533. 사회망서비스(SNS)
+import java.io.*;
+import java.util.*;
+
+class B2533 {
+    static int N;
+    static List<List<Integer>> adj;
+    static int[][] dp; // 행: 현재 노드가 얼리어답터인지 아닌지, 열: 현재 노드 번호, 값: 현재 노드부터 시작해서 리프까지 얼리어답터 최소 수
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        N = Integer.parseInt(br.readLine());
+        adj = new ArrayList<>();
+        dp = new int[2][N+1];
+
+        for(int i=0; i<=N; ++i) {
+            adj.add(new ArrayList<>());
+        }
+
+        for(int i=0; i<N-1; ++i) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+
+            adj.get(a).add(b);
+            adj.get(b).add(a);
+        }
+
+        dfs(1, 0);
+        System.out.println(Math.min(dp[0][1], dp[1][1]));
+    }
+
+    static void dfs(int cur, int prev) {
+        dp[0][cur] = 0;
+        dp[1][cur] = 1;
+
+        List<Integer> nexts = adj.get(cur);
+        for(int next : nexts) {
+            if(next == prev) continue;
+
+            dfs(next, cur);
+            dp[0][cur] += dp[1][next]; // cur가 얼리어가 아니므로, next가 무조건 얼리어야만 함
+            dp[1][cur] += Math.min(dp[1][next], dp[0][next]); // cur가 얼리어이므로, next는 뭐든 상관없음
+        }
+    }
+}
\ No newline at end of file