845. Longest Mountain in Array

Author: Partho Biswas

README.md

@@ -175,6 +175,7 @@ I have solved quite a number of problems from several topics. See the below tabl
 |64| **[379. Design Phone Directory](https://tinyurl.com/ybs3848v)** | [Python](https://tinyurl.com/wu6rdaw/379_Design_Phone_Directory.py), [Swift](https://tinyurl.com/wuja3c4/379_Design_Phone_Directory.swift) |  | Medium |  |
 |65| **[280. Wiggle Sort](https://tinyurl.com/ybnjn6fs)** | [Python](https://tinyurl.com/wu6rdaw/280_Wiggle_Sort.py), [Swift](https://tinyurl.com/wuja3c4/280_Wiggle_Sort.swift) |  | Medium |  |
 |66| [246. Strobogrammatic Number](https://tinyurl.com/ycqwsozh) | [Python](https://tinyurl.com/wu6rdaw/246_Strobogrammatic_Number.py), [Swift](https://tinyurl.com/wuja3c4/246_Strobogrammatic_Number.swift) |  | Easy |  |
+|67| **[845. Longest Mountain in Array](https://tinyurl.com/y9h5uah5)** | [Python](https://tinyurl.com/wu6rdaw/845_Longest_Mountain_in_Array.py), [Swift](https://tinyurl.com/wuja3c4/845_Longest_Mountain_in_Array.swift) |  | Medium |  |
 
 
 </p>
@@ -751,6 +752,7 @@ BFS, DFS, Dijkstra, Floyd–Warshall, Bellman-Ford, Kruskal, Prim's, Minimum Spa
 |10| [Spiral_Traverse](algoexpert.io/questions/Spiral_Traverse.md) | [Python](algoexpert.io/python/Spiral_Traverse.py) |
 |11| [Monotonic_Array](algoexpert.io/questions/Monotonic_Array.md) | [Python](algoexpert.io/python/Monotonic_Array.py) |
 |12| [Move_Element_To_End](algoexpert.io/questions/Move_Element_To_End.md) | [Python](algoexpert.io/python/Move_Element_To_End.py) |
+|13| [Longest_Peak](algoexpert.io/questions/Longest_Peak.md) | [Python](algoexpert.io/python/Longest_Peak.py) |
 
 </p>
 </details>

algoexpert.io/python/Longest_Peak.py

@@ -0,0 +1,23 @@
+def longestPeak(array):
+    longestPeakLen = 0
+    i = 1
+    while i < len(array) - 1:
+        isPeak = array[i - 1] < array[i] > array[i + 1]
+        if not isPeak:
+            i += 1
+            continue
+
+        leftIdx = i - 2
+        while leftIdx >= 0 and array[leftIdx] < array[leftIdx + 1]:
+            leftIdx -= 1
+
+        rightIdx = i + 2
+        while rightIdx < len(array) and array[rightIdx - 1] > array[rightIdx]:
+            rightIdx += 1
+
+        currentPeakLen = rightIdx - leftIdx - 1
+        longestPeakLen = max(longestPeakLen, currentPeakLen)
+        i = rightIdx
+
+    return longestPeakLen
+

leetcode.com/python/845_Longest_Mountain_in_Array.py

@@ -0,0 +1,28 @@
+class Solution(object):
+    def longestMountain(self, A):
+        """
+        :type A: List[int]
+        :rtype: int
+        """
+        longestPeakLen = 0
+        i = 1
+        while i < len(A) - 1:
+            isPeak = A[i - 1] < A[i] > A[i + 1]
+            if not isPeak:
+                i += 1
+                continue
+
+            leftIdx = i - 2
+            while leftIdx >= 0 and A[leftIdx] < A[leftIdx + 1]:
+                leftIdx -= 1
+
+            rightIdx = i + 2
+            while rightIdx < len(A) and A[rightIdx - 1] > A[rightIdx]:
+                rightIdx += 1
+
+            currentPeakLen = rightIdx - leftIdx - 1
+            longestPeakLen = max(longestPeakLen, currentPeakLen)
+            i = rightIdx
+
+        return longestPeakLen
+