diff --git a/solution/0800-0899/0845.Longest Mountain in Array/README.md b/solution/0800-0899/0845.Longest Mountain in Array/README.md
index 0bded80a711f8..09a6794dce130 100644
--- a/solution/0800-0899/0845.Longest Mountain in Array/README.md	
+++ b/solution/0800-0899/0845.Longest Mountain in Array/README.md	
@@ -67,7 +67,35 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def longestMountain(self, arr: List[int]) -> int:
+        left, right = 0, 1
+        status = -1
+        ans = 0
+        while right < len(arr):
+            if status == -1 or status == 1:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                if status == -1:
+                    if arr[right] > arr[right - 1]:
+                        status = 1
+                    else:
+                        left = right
+                if status == 1 and arr[right] < arr[right - 1]:
+                    status = 2
+            else:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                    ans = max(ans, right - left)
+                    left = right
+                elif arr[right] > arr[right - 1]:
+                    status = 1
+                    ans = max(ans, right - left)
+                    left = right - 1
+            right += 1
+        if status == 2:
+            ans = max(right - left, ans)
+        return ans
 ```
 
 ### **Java**
@@ -75,7 +103,44 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public int longestMountain(int[] arr) {
+        int left = 0, right = 0;
+        int ans = 0;
+        int status = -1;
+        while (++right < arr.length) {
+            if (status == -1 || status == 1) {
+                if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                }
+                if (status == -1) {
+                    if (arr[right] > arr[right - 1]) {
+                        status = 1;
+                    } else {
+                        left = right;
+                    }
+                }
+                if (status == 1 && arr[right] < arr[right - 1]) {
+                    status = 2;
+                }
+            } else {
+                if (arr[right] > arr[right - 1]) {
+                    status = 1;
+                    ans = Math.max(right - left, ans);
+                    left = right - 1;
+                } else if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                    ans = Math.max(right - left, ans);
+                    left = right;
+                }
+            }
+        }
+        if (status == 2) {
+            ans = Math.max(ans, right - left);
+        }
+        return ans;
+    }
+}
 ```
 
 ### **...**
diff --git a/solution/0800-0899/0845.Longest Mountain in Array/README_EN.md b/solution/0800-0899/0845.Longest Mountain in Array/README_EN.md
index fc783fcfc4ee6..36bd04e924caf 100644
--- a/solution/0800-0899/0845.Longest Mountain in Array/README_EN.md	
+++ b/solution/0800-0899/0845.Longest Mountain in Array/README_EN.md	
@@ -58,13 +58,78 @@
 ### **Python3**
 
 ```python
-
+class Solution:
+    def longestMountain(self, arr: List[int]) -> int:
+        left, right = 0, 1
+        status = -1
+        ans = 0
+        while right < len(arr):
+            if status == -1 or status == 1:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                if status == -1:
+                    if arr[right] > arr[right - 1]:
+                        status = 1
+                    else:
+                        left = right
+                if status == 1 and arr[right] < arr[right - 1]:
+                    status = 2
+            else:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                    ans = max(ans, right - left)
+                    left = right
+                elif arr[right] > arr[right - 1]:
+                    status = 1
+                    ans = max(ans, right - left)
+                    left = right - 1
+            right += 1
+        if status == 2:
+            ans = max(right - left, ans)
+        return ans
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public int longestMountain(int[] arr) {
+        int left = 0, right = 0;
+        int ans = 0;
+        int status = -1;
+        while (++right < arr.length) {
+            if (status == -1 || status == 1) {
+                if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                }
+                if (status == -1) {
+                    if (arr[right] > arr[right - 1]) {
+                        status = 1;
+                    } else {
+                        left = right;
+                    }
+                }
+                if (status == 1 && arr[right] < arr[right - 1]) {
+                    status = 2;
+                }
+            } else {
+                if (arr[right] > arr[right - 1]) {
+                    status = 1;
+                    ans = Math.max(right - left, ans);
+                    left = right - 1;
+                } else if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                    ans = Math.max(right - left, ans);
+                    left = right;
+                }
+            }
+        }
+        if (status == 2) {
+            ans = Math.max(ans, right - left);
+        }
+        return ans;
+    }
+}
 ```
 
 ### **...**
diff --git a/solution/0800-0899/0845.Longest Mountain in Array/Solution.java b/solution/0800-0899/0845.Longest Mountain in Array/Solution.java
new file mode 100644
index 0000000000000..7bd98b0893664
--- /dev/null
+++ b/solution/0800-0899/0845.Longest Mountain in Array/Solution.java	
@@ -0,0 +1,38 @@
+class Solution {
+    public int longestMountain(int[] arr) {
+        int left = 0, right = 0;
+        int ans = 0;
+        int status = -1;
+        while (++right < arr.length) {
+            if (status == -1 || status == 1) {
+                if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                }
+                if (status == -1) {
+                    if (arr[right] > arr[right - 1]) {
+                        status = 1;
+                    } else {
+                        left = right;
+                    }
+                }
+                if (status == 1 && arr[right] < arr[right - 1]) {
+                    status = 2;
+                }
+            } else {
+                if (arr[right] > arr[right - 1]) {
+                    status = 1;
+                    ans = Math.max(right - left, ans);
+                    left = right - 1;
+                } else if (arr[right] == arr[right - 1]) {
+                    status = -1;
+                    ans = Math.max(right - left, ans);
+                    left = right;
+                }
+            }
+        }
+        if (status == 2) {
+            ans = Math.max(ans, right - left);
+        }
+        return ans;
+    }
+}
\ No newline at end of file
diff --git a/solution/0800-0899/0845.Longest Mountain in Array/Solution.py b/solution/0800-0899/0845.Longest Mountain in Array/Solution.py
new file mode 100644
index 0000000000000..0b392748c2440
--- /dev/null
+++ b/solution/0800-0899/0845.Longest Mountain in Array/Solution.py	
@@ -0,0 +1,29 @@
+class Solution:
+    def longestMountain(self, arr: List[int]) -> int:
+        left, right = 0, 1
+        status = -1
+        ans = 0
+        while right < len(arr):
+            if status == -1 or status == 1:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                if status == -1:
+                    if arr[right] > arr[right - 1]:
+                        status = 1
+                    else:
+                        left = right
+                if status == 1 and arr[right] < arr[right - 1]:
+                    status = 2
+            else:
+                if arr[right] == arr[right - 1]:
+                    status = -1
+                    ans = max(ans, right - left)
+                    left = right
+                elif arr[right] > arr[right - 1]:
+                    status = 1
+                    ans = max(ans, right - left)
+                    left = right - 1
+            right += 1
+        if status == 2:
+            ans = max(right - left, ans)
+        return ans
\ No newline at end of file