[20250822] BOJ / P3 / 화려한 마을 / 이종환

Author: 0224LJH

0224LJH/202508/22 BOJ 화려한 마을

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+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.StringTokenizer;
+
+
+public class Main {
+	
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static StringBuilder sb = new StringBuilder();
+	static StringTokenizer st;
+	
+	static int houseCnt, nodeCnt, colorCnt, taskCnt;
+	
+	// 각각의 노드가 지금 구간에서 어떤 색을 몇 개 가지고 있는 지 인지해야함.
+	// 100,000 * 4 * 30 = 12,000,000 개의 Integer -> 이게 맞나?
+	
+	static class SegmentTree{
+		
+		int[] lazy;
+		int check;
+		int[] nodes; // 어느 색상을 가지는지 비트마스킹으로 표현. 이래서 색상이 최대가 30이었구나
+		
+		public SegmentTree() {
+			nodeCnt = houseCnt*4;
+			nodes = new int[nodeCnt];
+			lazy = new int[nodeCnt];
+			Arrays.fill(nodes, (1 << 1));
+		}
+		
+
+		
+		private void updateLazy(int nodeIdx, int from, int to) {
+			if (lazy[nodeIdx] ==0) return;
+			
+			nodes[nodeIdx] =  ( 1 << lazy[nodeIdx]);
+			
+			if ( from != to) {
+				lazy[nodeIdx*2] = lazy[nodeIdx];
+				lazy[nodeIdx*2+1] = lazy[nodeIdx];
+			}
+			lazy[nodeIdx] = 0;
+			
+			return;
+		}
+		
+		public void updateRnage(int from, int to , int target) {
+			updateRange(1,1,houseCnt, from,to,target);
+		}
+		
+		private void updateRange (int idx, int start, int end, int from ,int to, int target) {
+			updateLazy(idx, start, end);
+			
+			if ( start > to || end < from) return; // 아예 안걸림 
+			
+			
+			// 완전히 걸림
+			if ( start >= from && end <= to) {
+				
+				nodes[idx] = (1 << target);
+				
+				if (start!=end) {
+					lazy[idx*2] = target;
+					lazy[idx*2+1] = target;
+				}
+				return;
+			}
+			
+			//걸치는 경우
+			
+			int mid = (start+end)/2;
+			
+			// 하위 노드를 업데이트 후
+			updateRange(idx*2,start,mid,from,to,target);
+			updateRange(idx*2+1,mid+1,end,from,to,target);
+			
+
+			nodes[idx] =( nodes[idx*2] | nodes[idx*2+1]);
+		}
+		
+		public int query (int from, int to) {
+			check = 0 ;
+			query(1, 1, houseCnt, from,to);
+			
+			int ans = 0;
+			
+			for (int i = 0; i < 30; i++) {
+				if ( (check & (1 << i)) != 0) ans++;
+			}
+			return  ans;
+		}
+		
+		private void query(int idx, int start, int end, int from ,int to) {
+			updateLazy(idx, start, end);
+			
+			if (start > to || end < from) return;
+			
+			
+			if ( start >= from && end <= to) {
+				check |= nodes[idx];
+				return;
+			}
+			
+			// 적당히 겹치는 경우
+			int mid = (start+end)/2;
+			query(idx*2, start,mid,from,to);
+			query(idx*2+1, mid+1,end,from,to);
+		}
+		
+	}
+	
+
+	
+
+	public static void main(String[] args) throws IOException {
+		init();
+		process();
+		print();
+	}
+	
+	public static void init() throws IOException {
+		st = new StringTokenizer(br.readLine());
+		
+		houseCnt = Integer.parseInt(st.nextToken());
+		colorCnt = Integer.parseInt(st.nextToken());
+		taskCnt = Integer.parseInt(st.nextToken());
+		
+	}
+	
+	public static void process() throws IOException {
+		SegmentTree tree = new SegmentTree();
+		
+		for (int i = 0; i < taskCnt; i++) {
+			StringTokenizer st = new StringTokenizer(br.readLine());
+			String order = st.nextToken();
+			int from = Integer.parseInt(st.nextToken());
+			int to = Integer.parseInt(st.nextToken());
+			
+			if (from > to) {
+				int temp = from;
+				from = to;
+				to = temp;
+			}
+			
+			if (order.equals("C")){
+				int target = Integer.parseInt(st.nextToken());
+				tree.updateRnage(from, to, target);
+			} else {
+				sb.append(tree.query(from, to)).append("\n");
+			}
+		}
+
+	}
+
+	
+
+	public static void print() {
+		System.out.print(sb.toString());
+	}
+}
+
+```