9jinseok:: boj 1949_우수마을_고진석.java 추가

Author: 9jinseok

common/boj/1949/Main_1949_우수마을_고진석.java

@@ -0,0 +1,61 @@
+import java.io.*;
+import java.util.*;
+
+public class Main_1949_우수마을_고진석 {
+	static int N;
+	static int[] population;
+	static List<Integer>[] tree;
+	static int[][] dp;
+	static boolean[] visited;
+	
+	public static void main(String[] args) throws Exception{
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		StringTokenizer st;
+		
+		N = Integer.parseInt(br.readLine());
+		
+		population = new int[N + 1];
+		tree = new ArrayList[N + 1];
+		
+		st = new StringTokenizer(br.readLine());
+		for(int i = 1 ; i <= N ; i++) {
+			population[i] = Integer.parseInt(st.nextToken());
+			tree[i] = new ArrayList<>();
+		}
+		
+		for(int i = 0 ; i < N - 1 ;i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			tree[a].add(b);
+			tree[b].add(a);
+		}
+		
+		dp = new int[N + 1][2];
+		visited = new boolean[N + 1];
+		post(1);
+		
+		bw.write(Math.max(dp[1][1], dp[1][0]) + "\n");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+	
+	public static void post(int cur) {
+		visited[cur] = true;
+		
+		dp[cur][1] = population[cur];
+		dp[cur][0] = 0;
+		for(int to : tree[cur]) {
+			if(visited[to])
+				continue;
+			
+			post(to);
+			
+			dp[cur][1] += dp[to][0];
+			dp[cur][0] += Math.max(dp[to][0], dp[to][1]);
+		}
+	}
+	
+}