Find Peak Element.py

python/Find Peak Element.py

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+# A binary search based function  
+# that returns index of a peak element 
+def findPeakUtil(arr, low, high, n): 
+
+     # Find index of middle element 
+     # (low + high)/2  
+     mid = low + (high - low)/2 
+     mid = int(mid) 
+
+    # Compare middle element with its  
+    # neighbours (if neighbours exist) 
+    if ((mid == 0 or arr[mid - 1] <= arr[mid]) and 
+        (mid == n - 1 or arr[mid + 1] <= arr[mid])): 
+        return mid 
+
+
+    # If middle element is not peak and  
+    # its left neighbour is greater  
+    # than it, then left half must  
+    # have a peak element 
+    elif (mid > 0 and arr[mid - 1] > arr[mid]): 
+        return findPeakUtil(arr, low, (mid - 1), n) 
+
+    # If middle element is not peak and 
+    # its right neighbour is greater 
+    # than it, then right half must  
+    # have a peak element 
+    else: 
+        return findPeakUtil(arr, (mid + 1), high, n) 
+
+
+# A wrapper over recursive  
+# function findPeakUtil() 
+def findPeak(arr, n): 
+
+    return findPeakUtil(arr, 0, n - 1, n) 
+
+
+# Driver code 
+arr = [1, 3, 20, 4, 1, 0] 
+n = len(arr) 
+print("Index of a peak point is", findPeak(arr, n))