From 5a6752ef70a2a972213a06633f00b3d3d11edc33 Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Mon, 11 Aug 2025 23:55:49 +0900
Subject: [PATCH] 20250811 baekjoon

---
 code_study/Baekjoon/java/_1931.java | 43 ++++++++++++++++++++++++++
 code_study/Baekjoon/python/7569.py  | 48 +++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 code_study/Baekjoon/java/_1931.java
 create mode 100644 code_study/Baekjoon/python/7569.py

diff --git a/code_study/Baekjoon/java/_1931.java b/code_study/Baekjoon/java/_1931.java
new file mode 100644
index 0000000..e5418e7
--- /dev/null
+++ b/code_study/Baekjoon/java/_1931.java
@@ -0,0 +1,43 @@
+import java.util.*;
+
+class Meeting_Hour implements Comparable<Meeting_Hour>{
+    public int start;
+    public int end;
+
+    Meeting_Hour(int start, int end){
+        this.start = start;
+        this.end = end;
+    }
+
+    public int compareTo(Meeting_Hour another){
+        if(this.end == another.end) return this.start - another.start;
+        return this.end - another.end;
+    }
+}
+
+public class _1931 {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        ArrayList<Meeting_Hour> meetingList = new ArrayList<>();
+        int N = sc.nextInt();
+        for(int i=0; i<N; i++){
+            meetingList.add(new Meeting_Hour(sc.nextInt(),sc.nextInt()));
+        }
+        sc.close();
+
+        Collections.sort(meetingList);
+        // meetingList.sort((a,b)->{
+        //     if(a.end == b.end) return a.start - b.start;
+        //     return a.end - b.end;
+        // });
+        int currentEnd = meetingList.get(0).end;
+        int result = 1;
+        for(int i=1; i<N; i++){
+            if(currentEnd<=meetingList.get(i).start){
+                currentEnd = meetingList.get(i).end;
+                result++;
+            }
+        }
+        System.out.println(result);
+    }
+}
diff --git a/code_study/Baekjoon/python/7569.py b/code_study/Baekjoon/python/7569.py
new file mode 100644
index 0000000..0aa0ebe
--- /dev/null
+++ b/code_study/Baekjoon/python/7569.py
@@ -0,0 +1,48 @@
+import sys
+from collections import deque
+
+input = sys.stdin.readline
+
+N, M, H = map(int, input().split())
+visited = [[[-1]*N for _ in range(M)] for _ in range(H)]
+emptyCount = 0
+visitCount = 0
+q = deque()
+
+tomato = []
+for z in range(H):
+    tomato.append([])
+    for y in range(M):
+        row = list(map(int, input().split()))
+        tomato[z].append(row)
+        for x in range(N):
+            if row[x] == 1 :
+                q.append((z,y,x))
+                visited[z][y][x] = 0
+                visitCount += 1
+            
+            elif row[x] == -1 :
+                emptyCount += 1
+
+
+dx = [1,-1,0,0,0,0]
+dy = [0,0,1,-1,0,0]
+dz = [0,0,0,0,1,-1]
+dayMax = 0
+
+while len(q) :
+    cz, cy, cx = q.popleft()
+        
+    for i in range(6):
+        nz, ny, nx = cz + dz[i], cy + dy[i], cx + dx[i]
+        if 0<=nz<H and 0<=ny<M and 0<=nx<N and visited[nz][ny][nx] == -1 and tomato[nz][ny][nx] == 0:
+            q.append((nz,ny,nx))
+            visitCount += 1
+            visited[nz][ny][nx] = visited[cz][cy][cx] + 1
+            if visited[nz][ny][nx] > dayMax :
+                dayMax = visited[nz][ny][nx]
+    
+if N*M*H == visitCount + emptyCount :
+    print(dayMax)
+else :
+    print(-1)
\ No newline at end of file