[20251202] BOJ /G5 / 파티가 좋아 파티가 좋아 / 이종환

Author: 0224LJH

0224LJH/202512/02 BOJ 파티가 좋아 파티가 좋아.md

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+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.StringTokenizer;
+
+public class Main {
+   
+   static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+   static StringBuilder sb = new StringBuilder();
+   static int partyCnt,day;
+   static HashSet<Party> set;
+   
+   static class Party{
+      int start, end,idx;
+      
+      public Party(int start, int end, int idx) {
+    	 this.idx = idx;
+         this.start = start;
+         this.end = end;
+      }
+   }
+   
+    public static void main(String[] args) throws IOException {
+       day = 0;
+       while(true) {
+           partyCnt = Integer.parseInt(br.readLine());
+           if (partyCnt == 0 ) break;
+           init();
+           process();
+       }
+       print();
+
+    }
+    
+    private static void init() throws IOException{
+       day++;
+       set = new HashSet<>();
+       for (int i = 0; i < partyCnt; i++) {
+          StringTokenizer st = new StringTokenizer(br.readLine());
+          int start = Integer.parseInt(st.nextToken());
+          int end = Integer.parseInt(st.nextToken());
+          set.add(new Party(start, end,i));
+       }
+    }
+    
+    private static void process() throws IOException {
+       // 23시부터 시작, 제일 늦게 끝나는것부터 찾아서 넣기.
+       int cnt = 0;
+
+       for (int i = 23; i >= 8; i--) {
+
+          for (int j = 0; j < 2; j++) {
+              int maxDay = 0;
+              Party target = null;
+              for (Party p: set) {
+                  if (p.end > i && p.start <= i ) {
+                     if (maxDay < p.start) {
+                        maxDay = p.start;
+                        target = p;
+                     }
+                  }
+               }
+               
+               if (target != null) {
+                  set.remove(target);
+                  cnt++;
+               }
+          }
+       }
+       
+       String ans  = String.format("On day %d Emma can attend as many as %d parties.\n",day,cnt);
+       sb.append(ans);
+       
+    }
+    
+   private static void print() {
+      System.out.print(sb.toString());
+    }
+
+}
+```