diff --git "a/weekly/week01/BOJ_10828_\354\212\244\355\203\235/JAEHEE25.java" "b/weekly/week01/BOJ_10828_\354\212\244\355\203\235/JAEHEE25.java"
new file mode 100644
index 0000000..ca19e04
--- /dev/null
+++ "b/weekly/week01/BOJ_10828_\354\212\244\355\203\235/JAEHEE25.java"
@@ -0,0 +1,68 @@
+package stduy.week01;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+class BOJ10828 {
+	static int[] stack = new int[10001];
+	static int size;
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		int N = Integer.parseInt(br.readLine());
+		StringBuilder sb = new StringBuilder();
+		
+		for(int i = 0; i < N; i++) {
+			StringTokenizer st = new StringTokenizer(br.readLine());
+			String input = st.nextToken();
+			
+			switch (input) {
+			    case "push" :
+				    push(Integer.parseInt(st.nextToken()));
+				    break;
+			    case "pop" :
+				    sb.append(pop()).append("\n");
+				    break;
+			    case "size" :
+				    sb.append(size()).append("\n");
+				    break;
+			    case "empty" :
+				    sb.append(empty()).append("\n");
+				    break;
+			    case "top" :
+				    sb.append(top()).append("\n");
+				    break;
+			}
+		}
+		System.out.println(sb);
+	}
+	
+	public static void push(int num) {
+		stack[size++] = num;
+	}
+	
+	public static int pop() {
+		if (size == 0) return -1;
+		else {
+			int pop = stack[size - 1];
+			size--;
+			return pop;
+		}
+	}
+	
+	public static int size() {
+		return size;
+	}
+	
+	public static int empty() {
+		if (size == 0) return 1;
+		return 0;
+	}
+	
+	public static int top() {
+		if (size == 0) return -1;
+		return stack[size - 1];
+	}
+
+}
diff --git "a/weekly/week01/BOJ_1920_\354\210\230 \354\260\276\352\270\260/JAEHEE25.java" "b/weekly/week01/BOJ_1920_\354\210\230 \354\260\276\352\270\260/JAEHEE25.java"
new file mode 100644
index 0000000..d22d0bf
--- /dev/null
+++ "b/weekly/week01/BOJ_1920_\354\210\230 \354\260\276\352\270\260/JAEHEE25.java"	
@@ -0,0 +1,33 @@
+package stduy.week01;
+
+import java.io.*;
+import java.util.*;
+
+class BOJ1920 {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int n = Integer.parseInt(br.readLine());
+        int[] arr = new int[n];
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < n; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+        int m = Integer.parseInt(br.readLine());
+
+        Arrays.sort(arr);
+
+        StringBuilder sb = new StringBuilder();
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < m; i++) {
+            int num = Integer.parseInt(st.nextToken());
+            int in = Arrays.binarySearch(arr, num);
+
+            if (in < 0) {
+                sb.append(0 + "\n");
+            } else {
+                sb.append(1 + "\n");
+            }
+        }
+        System.out.println(sb);
+    }
+}
diff --git "a/weekly/week01/BOJ_2750_\354\210\230 \354\240\225\353\240\254\355\225\230\352\270\260/JAEHEE25.java" "b/weekly/week01/BOJ_2750_\354\210\230 \354\240\225\353\240\254\355\225\230\352\270\260/JAEHEE25.java"
new file mode 100644
index 0000000..be2fe0a
--- /dev/null
+++ "b/weekly/week01/BOJ_2750_\354\210\230 \354\240\225\353\240\254\355\225\230\352\270\260/JAEHEE25.java"	
@@ -0,0 +1,24 @@
+package stduy.week01;
+
+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class BOJ2750 {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int N = Integer.parseInt(br.readLine());
+        int[] arr = new int[N];
+        for (int i = 0; i < N; i++) {
+            arr[i] = Integer.parseInt(br.readLine());
+        }
+
+        Arrays.sort(arr);
+
+        StringBuilder answer = new StringBuilder();
+        for (int i = 0; i < N; i++) {
+            answer.append(arr[i]).append("\n");
+        }
+        System.out.println(answer);
+    }
+}