diff --git "a/BOJ/1000-5000\353\262\210/JY_1911.java" "b/BOJ/1000-5000\353\262\210/JY_1911.java"
new file mode 100644
index 00000000..7b11d13e
--- /dev/null
+++ "b/BOJ/1000-5000\353\262\210/JY_1911.java"
@@ -0,0 +1,72 @@
+package day1029;
+
+import java.io.*;
+import java.util.*;
+
+public class JY_1911 {
+	
+	static int N, L;
+	static long[][] hrr;
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		N = Integer.parseInt(st.nextToken());
+		L = Integer.parseInt(st.nextToken());
+		
+		hrr = new long[N][2];
+		for(int i=0; i<N; i++) {
+			st = new StringTokenizer(br.readLine());
+			hrr[i][0] = Integer.parseInt(st.nextToken());
+			hrr[i][1] = Integer.parseInt(st.nextToken());
+		}
+		
+		// 물웅덩이 위치순으로 정렬
+		Arrays.sort(hrr, (o1, o2)->Long.compare(o1[0], o2[0]));
+		
+		long s = 0;
+		long e = hrr[N-1][1];	// 최대의 널빤지수 == L이 1이고, 가장 마지막 물웅덩이까지 다 덮을 때 
+		long cnt = 0;
+		
+		while(s <= e) {
+			long mid = (s + e) / 2;
+			
+			if(isPossible(mid)) {
+				cnt = mid;
+				e = mid - 1;
+			}else {
+				s = mid + 1;
+			}
+		}
+		
+		System.out.println(cnt);
+
+	}
+	public static boolean isPossible(long mid) {
+		long pre = 0;				// 마지막 널빤지 위치
+		long total = 0;				// 총 필요한 널빤지 개수
+		for(int i=0; i<N; i++) {
+			long[] now = hrr[i];
+			// 현재 물웅덩이 시작점에 널빤지 없다면 새로운 널빤지 시작점
+			if(pre < now[0]) {
+				pre = now[0];
+			} 
+			
+			// 물 웅덩이 크기
+			long size = now[1] - pre;
+			if(size <= 0) continue;
+			
+			// 필요한 널빤지 개수
+			long cnt = (size / L);
+			if(size % L != 0) cnt++;
+			total += cnt;
+			if(total > mid) return false;
+			
+			pre = pre + cnt * L;	// 마지막 널빤지 위치 갱신
+		}
+		
+		return true;
+	}
+
+}
diff --git "a/BOJ/1000-5000\353\262\210/JY_2461.java" "b/BOJ/1000-5000\353\262\210/JY_2461.java"
new file mode 100644
index 00000000..8ce2960c
--- /dev/null
+++ "b/BOJ/1000-5000\353\262\210/JY_2461.java"
@@ -0,0 +1,60 @@
+package day1031;
+
+import java.io.*;
+import java.util.*;
+
+public class JY_2461 {
+
+	public static void main(String[] args) throws IOException{
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		int N = Integer.parseInt(st.nextToken());
+		int M = Integer.parseInt(st.nextToken());
+		
+		int[][] srr = new int[N][M];
+		for(int i=0; i<N; i++) {
+			st = new StringTokenizer(br.readLine());
+			for(int j=0; j<M; j++) {
+				srr[i][j] = Integer.parseInt(st.nextToken());
+			}
+		}
+		
+		// 각 반 정렬
+		for(int i=0; i<N; i++) {
+			Arrays.sort(srr[i]);
+		}
+		
+		// 각 반의 학생 인덱스 포인터 배열
+		int[] n = new int[N];
+		
+		int ans = Integer.MAX_VALUE;
+		while(true) {
+			int max = Integer.MIN_VALUE;
+			int min = Integer.MAX_VALUE;
+			int minIdx = -1;
+			
+			// 각 반 반복
+			for(int i=0; i<N; i++) {
+				int j = n[i];         // 각 반이 현재 가리키고 있는 학생
+				if(max < srr[i][j]) {
+					max = srr[i][j];
+				}
+				if(min > srr[i][j]) {
+					min = srr[i][j];
+					minIdx = i;
+				}
+			}
+
+			ans = Math.min(ans, max-min);
+			n[minIdx]++;
+			if(n[minIdx] == M) break;
+			
+		}
+		
+		System.out.println(ans);
+		
+	}
+	
+
+}
diff --git "a/BOJ/20001-25000\353\262\210/JY_20007.java" "b/BOJ/20001-25000\353\262\210/JY_20007.java"
new file mode 100644
index 00000000..37512909
--- /dev/null
+++ "b/BOJ/20001-25000\353\262\210/JY_20007.java"
@@ -0,0 +1,125 @@
+package day1030;
+
+import java.io.*;
+import java.util.*;
+
+public class JY_20007 {
+	
+	static long INF = Long.MAX_VALUE;
+	static int N, M, X, Y;
+	static List<Node>[] g;
+	static long[] distance;
+	static class Node implements Comparable<Node> {
+		int n;
+		long dist;
+
+		public Node(int n, long dist) {
+			super();
+			this.n = n;
+			this.dist = dist;
+		}
+		@Override
+		public int compareTo(Node other) {
+			return Long.compare(this.dist, other.dist);
+		}
+
+		@Override
+		public String toString() {
+			return "Node [n=" + n + ", dist=" + dist + "]";
+		}
+		
+	}
+	
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		X = Integer.parseInt(st.nextToken());
+		Y = Integer.parseInt(st.nextToken());
+		
+		g = new ArrayList[N];
+		for(int i=0; i<N; i++) {
+			g[i] = new ArrayList<>();
+		}
+		
+		distance = new long[N];
+		for(int i=0; i<N; i++) {
+			distance[i] = INF;
+		}
+		
+		for(int i=0; i<M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			int c = Integer.parseInt(st.nextToken());
+			g[a].add(new Node(b, c));
+			g[b].add(new Node(a, c));
+		}
+		
+		dijkstra(Y);
+		
+		Arrays.sort(distance);
+		
+//		System.out.println(Arrays.toString(distance));
+		
+		// 갈 수없는 곳 찾기
+		for(int i=N-1; i>=0; i--) {
+			if(2*distance[i] > X) {
+				System.out.println(-1);
+				return;
+			}
+		}
+		
+		// 투포인터 이거 왜안되죠???
+		// X= 21, distance = [0, 1, 1, 9, 9]이면 최소일수는 2일아닌가요??!! ㅠ0ㅠ
+//		int s = 0;
+//		int e = N-1;
+//		long sum = 2*distance[e];
+//		while(s <= e) {
+//			if(sum + 2*distance[s] <= X) {
+//				sum += 2*distance[s];
+//				s++;
+//			} else {
+//				e--;
+//				ans++;
+//				sum = 2*distance[e];
+//			}
+//		}
+		
+		int ans = 1;
+		long sum = 0;
+		for(int i=0; i<N; i++) {
+			if(sum + 2*distance[i] > X) {
+				ans++;
+				sum = 2*distance[i];
+			} else {
+				sum += 2*distance[i];
+			}
+		}
+		
+		System.out.println(ans);
+		
+	}
+	public static void dijkstra(int start) {
+		distance[start] = 0;
+		PriorityQueue<Node> pq = new PriorityQueue<>();
+		pq.add(new Node(start, 0));
+		
+		while(!pq.isEmpty()) {
+			Node now = pq.poll();
+			
+			if(distance[now.n] < now.dist) continue;
+			
+			for(Node next: g[now.n]) {
+				long cost = now.dist + next.dist;
+				if(distance[next.n] > cost) {
+					distance[next.n] = cost;
+					pq.add(new Node(next.n, cost));
+				}
+			}
+		}
+	}
+
+}
diff --git "a/BOJ/5001-10000\353\262\210/JY_9342.java" "b/BOJ/5001-10000\353\262\210/JY_9342.java"
new file mode 100644
index 00000000..c6d1cbac
--- /dev/null
+++ "b/BOJ/5001-10000\353\262\210/JY_9342.java"
@@ -0,0 +1,72 @@
+package day1029;
+
+import java.io.*;
+import java.util.*;
+
+public class JY_9342 {
+	
+	static boolean isOk;
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		
+		int T = Integer.parseInt(br.readLine());
+		for(int t=0; t<T; t++) {
+			String str = br.readLine();
+			
+			isOk = false;
+			isGen(str, 0, 0);
+			if(!isOk) System.out.println("Good");
+			else System.out.println("Infected!");
+		}
+
+	}
+	/*
+	 * << type >> 규칙
+	 * 0 : 문자열은 {A, B, C, D, E, F} 중 0개 또는 1개로 시작해야 한다.
+	 * 1 : 그 다음에는 A가 하나 또는 그 이상 있어야 한다.
+	 * 2 : 그 다음에는 F가 하나 또는 그 이상 있어야 한다.
+	 * 3 : 그 다음에는 C가 하나 또는 그 이상 있어야 한다.
+	 * 4 : 그 다음에는 {A, B, C, D, E, F} 중 0개 또는 1개가 있으며, 더 이상의 문자는 없어야 한다.
+	 * */
+	public static void isGen(String s, int idx, int type) {
+		if(type == 0) {
+			if(s.charAt(idx) >= 'A' && s.charAt(idx) <= 'F') {
+				if(s.charAt(idx) == 'A') isGen(s, idx, 1); 		// 다음 조건도 A로 시작하므로 인덱스 증가X
+				else isGen(s, idx+1, 1);
+			}
+		} else if(type == 1) {
+			int next = check(s, idx, 'A');
+			if(next != -1) {
+				isGen(s, next, 2);
+			}
+		} else if(type == 2) {
+			int next = check(s, idx, 'F');
+			if(next != -1) {
+				isGen(s, next, 3);
+			}
+		} else if(type == 3) {
+			int next = check(s, idx, 'C');
+			if(next != -1) {
+				isGen(s, next, 4);
+			}
+		} else {
+			if(idx == s.length()) isOk = true;
+			else if(idx == s.length()-1 && s.charAt(idx) >= 'A' && s.charAt(idx) <= 'F') {
+				isOk = true;
+			}
+		}
+	}
+	public static int check(String s, int idx, char c) {
+		int i = idx;
+		while(i < s.length()) {
+			if(s.charAt(i) != c) break;
+			i++;
+		}
+		if(i > idx) {
+			return i;
+		}
+		return -1;
+	}
+
+}
diff --git a/Programmers/Level2/JY_150369.java b/Programmers/Level2/JY_150369.java
new file mode 100644
index 00000000..7cdb216a
--- /dev/null
+++ b/Programmers/Level2/JY_150369.java
@@ -0,0 +1,53 @@
+import java.util.*;
+
+class Solution {
+    public long solution(int cap, int n, int[] deliveries, int[] pickups) {
+        long answer = 0;
+        
+        int i = n-1;
+        while(i >= 0) {
+            System.out.println("i: "+i);
+            System.out.println("d: "+Arrays.toString(deliveries));
+            System.out.println("p: "+Arrays.toString(pickups));
+            
+            // 배달과 수거 모두 끝난 집은 pass
+            if(deliveries[i] ==0 && pickups[i] ==0){
+                i--;
+                continue;
+            }
+            
+            // 현재 가장 먼 집위치
+            int start = i+1;
+            
+            // 배달하기
+            int capD = cap;
+            int d = i;
+            while(d >= 0) {
+                if(capD < deliveries[d]) {
+                    deliveries[d] -= capD;
+                    break;
+                }
+                capD -= deliveries[d];
+                deliveries[d] = 0;
+                d--;
+            }
+            
+            // 수거하기
+            int capP = cap;
+            int p = i;
+            while(p >= 0) {
+                if(capP < pickups[p]) {
+                    pickups[p] -= capP;
+                    break;
+                }
+                capP -= pickups[p];
+                pickups[p] = 0;
+                p--;
+            }
+            
+            answer += (start*2);
+        }
+        
+        return answer;
+    }
+}
\ No newline at end of file
diff --git "a/SQL/08\354\243\274\354\260\250/JY_Game_Play_Analysis_IV.sql" "b/SQL/08\354\243\274\354\260\250/JY_Game_Play_Analysis_IV.sql"
new file mode 100644
index 00000000..2f91d508
--- /dev/null
+++ "b/SQL/08\354\243\274\354\260\250/JY_Game_Play_Analysis_IV.sql"
@@ -0,0 +1,7 @@
+-- 550. Game Play Analysis IV
+-- https://leetcode.com/problems/game-play-analysis-iv/?envType=study-plan-v2&envId=top-sql-50
+SELECT ROUND(COUNT(DISTINCT A.player_id) / (SELECT COUNT(DISTINCT player_id) FROM activity), 2) AS fraction
+FROM activity A
+JOIN activity B
+on A.player_id = B.player_id
+WHERE (A.player_id, A.event_date) in (SELECT player_id, min(event_date) FROM activity group by player_id) AND DATEDIFF(B.event_date, A.event_date) = 1
\ No newline at end of file
diff --git "a/SQL/08\354\243\274\354\260\250/JY_Immediate_Food_Delivery_II.sql" "b/SQL/08\354\243\274\354\260\250/JY_Immediate_Food_Delivery_II.sql"
new file mode 100644
index 00000000..7e3f59bb
--- /dev/null
+++ "b/SQL/08\354\243\274\354\260\250/JY_Immediate_Food_Delivery_II.sql"
@@ -0,0 +1,6 @@
+-- 1174. Immediate Food Delivery II
+-- https://leetcode.com/problems/immediate-food-delivery-ii/?envType=study-plan-v2&envId=top-sql-50
+select round(count(customer_id)/(select count(distinct customer_id) from delivery), 4)*100 as immediate_percentage
+from delivery
+where order_date = customer_pref_delivery_date
+      and (customer_id, order_date) in (select customer_id, min(order_date) from delivery group by customer_id)
\ No newline at end of file