Completed Binary Search 2

Problem_1.py

@@ -0,0 +1,45 @@
+class Solution:
+    def getFirst(self, low, high, target, nums):
+        ans = -1
+        while low <= high:
+            mid = low + (high - low) // 2
+            curr = nums[mid]
+            if curr == target:
+                ans = mid
+                high = mid - 1
+            elif target < curr:
+                high = mid - 1
+            else:
+                low = mid + 1
+        return ans
+
+    def getLast(self, low, high, target, nums):
+        ans = -1
+        while low <= high:
+            mid = low + (high - low) // 2
+            curr = nums[mid]
+            if curr == target:
+                ans = mid
+                low = mid + 1
+            elif target < curr:
+                high = mid - 1
+            else:
+                low = mid + 1
+        return ans
+
+    def searchRange(self, nums, target):
+        n = len(nums)
+        low, high = 0, n - 1
+        ans = [-1, -1]
+        ans[0] = self.getFirst(low, high, target, nums)
+        if ans[0] == -1:
+            return ans
+        ans[1] = self.getLast(low, high, target, nums)
+        return ans
+
+
+
+nums = [5,7,7,8,8,10]
+target = 8
+sl = Solution()
+print(sl.searchRange(nums,target))

Problem_2.py

@@ -0,0 +1,24 @@
+import math
+
+class Solution:
+    def findMin(self, nums):
+        n = len(nums)
+        low,high = 0, n-1
+        ans = math.inf
+        while low <= high:
+            mid = low + (high-low)//2
+            curr = nums[mid]
+            if nums[low] <= curr:
+                ans = min(ans,nums[low])
+                low = mid + 1
+            else:
+                ans = min(ans,curr)
+                high = mid - 1
+        return ans
+
+
+
+# nums = [3,4,5,1,2]
+nums = [2,1]
+sl = Solution()
+print(sl.findMin(nums))

Problem_3.py

@@ -0,0 +1,18 @@
+class Solution:
+    def findPeakElement(self, nums):
+        n = len(nums)
+        low,high  = 0, n-1
+        while low <= high:
+            mid = low + (high - low)//2
+            curr = nums[mid]
+            if (mid == 0 or nums[mid-1] < curr) and (mid == n-1 or nums[mid+1] < curr):
+                return mid
+            if nums[mid-1] < curr:
+                low = mid + 1
+            else:
+                high = mid - 1
+        return -1
+
+nums = [1,2,1,3,5,6,4]
+sl = Solution()
+print(sl.findPeakElement(nums))