added alternate binary search | added peak element

Author: mihirs16

04. Algorithms/Searching/Alt_Binary_Search.py

@@ -0,0 +1,20 @@
+# alternative binary search
+# - based on "efficient iteration"
+# - make jumps and slow down as we get close to target 
+# - time complexity => O(logn)
+
+# iterative
+def bsearch_alt(target, arr):
+    n = len(arr)
+    k = 0
+    i = n // 2
+    while (i >= 1):
+        while (k + i < n) and (arr[k + i] <= target):
+            k = k + 1
+        i = i // 2
+    
+    return k if arr[k] == target else -1
+
+
+
+print(bsearch_alt(4, [1, 2, 3, 4, 5]))

14. Questions/leetcode 162 - peak element.py

@@ -0,0 +1,16 @@
+# find peak element | leetcode 162 | https://leetcode.com/problems/find-peak-element/
+# using binary search to determine 
+# if the "middle" element is on a +ve / -ve slope
+
+class Solution:
+    def findPeakElement(self, nums: list[int]) -> int:
+        a = 0
+        b = len(nums) - 1
+        while a < b:
+            k = (a + b) // 2
+            if nums[k] > nums[k + 1]:
+                b = k
+            else:
+                a = k + 1
+                
+        return a