diff --git a/src/main/java/com/code/leet/doubleWeek/MovieRentingSystem.java b/src/main/java/com/code/leet/doubleWeek/MovieRentingSystem.java
new file mode 100644
index 0000000..3219037
--- /dev/null
+++ b/src/main/java/com/code/leet/doubleWeek/MovieRentingSystem.java
@@ -0,0 +1,24 @@
+//package com.code.leet.doubleWeek;
+//
+//public class MovieRentingSystem {
+//
+//    public MovieRentingSystem(int n, int[][] entries) {
+//
+//    }
+//
+//    public List<Integer> search(int movie) {
+//
+//    }
+//
+//    public void rent(int shop, int movie) {
+//
+//    }
+//
+//    public void drop(int shop, int movie) {
+//
+//    }
+//
+//    public List<List<Integer>> report() {
+//
+//    }
+//}
diff --git a/src/main/java/com/code/leet/doubleWeek/SolutionD55.java b/src/main/java/com/code/leet/doubleWeek/SolutionD55.java
new file mode 100644
index 0000000..86457e7
--- /dev/null
+++ b/src/main/java/com/code/leet/doubleWeek/SolutionD55.java
@@ -0,0 +1,72 @@
+package com.code.leet.doubleWeek;
+
+import java.util.Arrays;
+
+public class SolutionD55 {
+    public static void main(String[] args) {
+        SolutionD55 solution = new SolutionD55();
+//        System.out.println(solution.canBeIncreasing(new int[]{2, 3, 1, 2}));
+        System.out.println(solution.maxAlternatingSum(new int[]{2, 1, 5, 4, 4}));
+    }
+
+    public boolean canBeIncreasing(int[] nums) {
+        return countDel(nums, 0) < 2;
+    }
+
+    private int countDel(int[] nums, int count) {
+        int size = nums.length - 1;
+        for (int i = 0; i < size; i++) {
+            if (nums[i] >= nums[i + 1]) {
+                count++;
+                int[] aft;
+                int[] bef;
+                if (i > 0) {
+                    bef = new int[size - i + 1];
+                    bef[0] = nums[i - 1];
+                    for (int j = i + 1; j <= size; j++) {
+                        bef[j - i] = nums[j];
+                    }
+                    aft = Arrays.copyOf(bef, size - i + 1);
+                    aft[1] = nums[i];
+                } else {
+                    bef = Arrays.copyOfRange(nums, 1, size);
+                    aft = bef;
+                }
+                count = Math.min(countDel(bef, count), countDel(aft, count));
+                if (count > 2) {
+                    return count;
+                }
+            }
+        }
+        return count;
+    }
+
+    public String removeOccurrences(String s, String part) {
+        while (s.contains(part)) {
+            s = s.replace(part, "");
+        }
+        return s;
+    }
+
+    public long maxAlternatingSum(int[] nums) {
+        if (nums.length == 1) {
+            return nums[0];
+        }
+        if (nums.length == 2) {
+            return Math.max(nums[0], nums[1]);
+        }
+        int[] temp = Arrays.copyOfRange(nums, 1, nums.length);
+        return Math.max(nums[0] - min(temp), maxAlternatingSum(temp));
+    }
+
+    private long min(int[] nums) {
+        if (nums.length == 1) {
+            return nums[0];
+        }
+        if (nums.length == 2) {
+            return Math.min(nums[0] - nums[1], nums[1] - nums[0]);
+        }
+        int[] temp = Arrays.copyOfRange(nums, 1, nums.length);
+        return Math.min(nums[0] - maxAlternatingSum(temp), min(temp));
+    }
+}