diff --git "a/week39/\354\235\264\354\203\201\354\226\265/backjoon/A\354\231\200_B.java" "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/A\354\231\200_B.java"
new file mode 100644
index 0000000..3546d54
--- /dev/null
+++ "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/A\354\231\200_B.java"
@@ -0,0 +1,29 @@
+import java.io.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String S = br.readLine();
+        StringBuilder T = new StringBuilder(br.readLine());
+
+        while (T.length() > S.length()) {
+            char last = T.charAt(T.length() - 1);
+
+            if (last == 'A') {
+                // 맨 뒤 A 제거
+                T.deleteCharAt(T.length() - 1);
+            } else {
+                // 맨 뒤 B 제거 후 뒤집기
+                T.deleteCharAt(T.length() - 1);
+                T.reverse();
+            }
+        }
+
+        if (T.toString().equals(S)) {
+            System.out.println(1);
+        } else {
+            System.out.println(0);
+        }
+    }
+}
diff --git "a/week39/\354\235\264\354\203\201\354\226\265/backjoon/\352\265\254\353\221\220_\354\210\230\354\204\240\352\263\265.java" "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\352\265\254\353\221\220_\354\210\230\354\204\240\352\263\265.java"
new file mode 100644
index 0000000..c831eac
--- /dev/null
+++ "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\352\265\254\353\221\220_\354\210\230\354\204\240\352\263\265.java"
@@ -0,0 +1,29 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int N = Integer.parseInt(br.readLine());
+
+        List<int[]> tasks = new ArrayList<>();
+        for (int i = 0; i < N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int T = Integer.parseInt(st.nextToken());
+            int S = Integer.parseInt(st.nextToken());
+            tasks.add(new int[]{T, S, i + 1}); // 시간 , 벌금 , 순서
+        }
+
+        tasks.sort((a, b) -> {
+            long comp = (long)b[1] * a[0] - (long)a[1] * b[0]; //
+            if (comp != 0) return comp > 0 ? 1 : -1;
+            return a[2] - b[2];
+        });
+
+        StringBuilder sb = new StringBuilder();
+        for (int[] task : tasks) {
+            sb.append(task[2]).append(" ");
+        }
+        System.out.println(sb.toString().trim());
+    }
+}
diff --git "a/week39/\354\235\264\354\203\201\354\226\265/backjoon/\353\202\264\353\246\254\353\247\211\352\270\270.java" "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\353\202\264\353\246\254\353\247\211\352\270\270.java"
new file mode 100644
index 0000000..28acf0c
--- /dev/null
+++ "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\353\202\264\353\246\254\353\247\211\352\270\270.java"
@@ -0,0 +1,22 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        int M = Integer.parseInt(st.nextToken());
+        int N = Integer.parseInt(st.nextToken());
+
+        int[][] map = new int[M][N];
+
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < N; j++) {
+                map[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+    }
+}
diff --git "a/week39/\354\235\264\354\203\201\354\226\265/backjoon/\354\235\264\354\240\204_\354\210\234\354\227\264.java" "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\354\235\264\354\240\204_\354\210\234\354\227\264.java"
new file mode 100644
index 0000000..fced62d
--- /dev/null
+++ "b/week39/\354\235\264\354\203\201\354\226\265/backjoon/\354\235\264\354\240\204_\354\210\234\354\227\264.java"
@@ -0,0 +1,57 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static void swap(int[] arr, int a, int b) {
+        int tmp = arr[a];
+        arr[a] = arr[b];
+        arr[b] = tmp;
+    }
+
+    static void reverse(int[] arr, int start, int end) {
+        while (start < end) {
+            swap(arr, start, end);
+            start++;
+            end--;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        int N = Integer.parseInt(br.readLine());
+        int[] arr = new int[N];
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+
+        int i = N - 1;
+        while (i > 0 && arr[i - 1] < arr[i]) { // 오름차순 깨지는 구간
+            i--;
+        }
+
+        if (i == 0) {
+            System.out.println(-1);
+            return;
+        }
+
+        int j = N - 1;
+        while (arr[j] > arr[i - 1]) { // 내림차순 깨지는 구간
+            j--;
+        }
+
+        swap(arr, i - 1, j);
+
+        reverse(arr, i, N - 1);
+
+        StringBuilder sb = new StringBuilder();
+        for (int k = 0; k < N; k++) {
+            sb.append(arr[k]).append(" ");
+        }
+        System.out.println(sb.toString().trim());
+    }
+}