diff --git a/0503/BOJ/P1620/P1620_yu.java b/0503/BOJ/P1620/P1620_yu.java
new file mode 100644
index 0000000..71491c9
--- /dev/null
+++ b/0503/BOJ/P1620/P1620_yu.java
@@ -0,0 +1,42 @@
+import java.util.HashMap;
+import java.util.Scanner;
+
+public class bj_1620_나는야포켓몬마스터이다솜 {
+public static void main(String[] args) {
+	
+	// 참고사항) 배열을 돌며 찾았더니 시간초과. 백만은 무리.
+	
+	Scanner sc = new Scanner(System.in);
+	
+	int N = sc.nextInt(); // 포켓몬 보유 수
+	int M = sc.nextInt(); // 맞춰야 하는 수
+	
+	HashMap<String, Integer> findidx = new HashMap<>(); // 포켓몬 인덱스 출력
+	HashMap<Integer, String> findpk = new HashMap<>(); // 포켓몬 출력
+	
+	
+	for(int i=1; i<=N; i++) {
+		
+		String monster = sc.next();
+		findidx.put(monster, i); // 인덱스저장
+		findpk.put(i, monster);  // 포켓몬저장
+	}
+	
+	StringBuilder sb = new StringBuilder();
+	
+	for(int i=0; i<M; i++) {
+		String word = sc.next();
+		
+		if(word.charAt(0)>='1' && word.charAt(0) <='9') {
+			// 만약 숫자면 해당 포켓몬 이름 출력
+			int idx = Integer.parseInt(word);
+			sb.append(findpk.get(idx));
+		}else {
+			// 포켓몬이면 해당 인덱스 출력
+			sb.append(findidx.get(word));
+		}
+		sb.append("\n");
+	}
+	System.out.println(sb);
+}
+}
diff --git a/0503/BOJ/P1676/P1676_yu.java b/0503/BOJ/P1676/P1676_yu.java
new file mode 100644
index 0000000..e1ffb2c
--- /dev/null
+++ b/0503/BOJ/P1676/P1676_yu.java
@@ -0,0 +1,35 @@
+import java.util.Scanner;
+
+public class bj_1676_팩토리얼0의개수 {
+	public static void main(String[] args) {
+
+		Scanner sc = new Scanner(System.in);
+
+		int N = sc.nextInt(); 
+
+		int cnt2 = 0;
+		int cnt5 = 0;
+		
+		// 2*5 쌍의 결과가 0이 나오므로 쌍 개수가 답이 됨
+
+		for(int i=1; i<=N; i++) {
+			
+			int num = i;
+			
+			while(num % 2 == 0) {
+				cnt2++;
+				num /= 2;
+			}
+			
+			while(num% 5 == 0) {
+				cnt5++;
+				num /= 5;
+			}
+		}
+		
+		
+		
+		System.out.println(Math.min(cnt2, cnt5));
+	}
+
+}
diff --git a/0503/Programmers/Lv1/Lv1_yu.java b/0503/Programmers/Lv1/Lv1_yu.java
new file mode 100644
index 0000000..4dc9414
--- /dev/null
+++ b/0503/Programmers/Lv1/Lv1_yu.java
@@ -0,0 +1,44 @@
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class lv1_로또의최고순위와최저순위 {
+	public static void main(String[] args) {
+
+		int[] lottos = { 44, 1, 0, 0, 31, 25 };
+		int[] win_nums = { 31, 10, 45, 1, 6, 19 };
+
+		//
+
+		List<Integer> win = new ArrayList<>();
+
+		for (int i = 0; i < win_nums.length; i++) {
+			win.add(win_nums[i]);
+		}
+
+		int[] rank = { 6, 6, 5, 4, 3, 2, 1 };
+
+		int zerocnt = 0;
+		int same = 0;
+
+		for (int i = 0; i < lottos.length; i++) {
+
+			if (lottos[i] == 0) {
+				zerocnt++;
+			}
+
+			if (win.contains(lottos[i])) {
+				same++;
+			}
+		}
+
+		int[] answer = new int[2];
+
+		answer[0] = rank[same + zerocnt];
+		answer[1] = rank[same];
+
+		System.out.println(Arrays.toString(answer));
+
+	}
+
+}
diff --git a/0503/Programmers/Lv3/Lv3_yu.java b/0503/Programmers/Lv3/Lv3_yu.java
new file mode 100644
index 0000000..92fa794
--- /dev/null
+++ b/0503/Programmers/Lv3/Lv3_yu.java
@@ -0,0 +1,38 @@
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Deque;
+
+public class lv3_숫자게임 {
+	public static void main(String[] args) {
+
+		int[] A = { 5, 1, 3, 7 };
+		int[] B = { 2, 2, 6, 8 };
+		int answer = 0;
+		//
+		
+		// 질 땐 크게 지고, 이길 땐 비슷하게 이기자~
+
+		Arrays.sort(A);
+		Arrays.sort(B);
+
+		Deque<Integer> game = new ArrayDeque<>();
+
+		int n = A.length;
+
+		for (int i = 0; i < n; i++) {
+			game.add(B[i]);
+		}
+		
+		
+		for (int i = n - 1; i >= 0; i--) {
+
+			if (A[i] >= game.peekLast()) {
+				game.pollFirst();
+			} else {
+				game.pollLast();
+				answer++;
+			}
+		}
+		System.out.println(answer);
+	}
+}