Added competative coding problems

Problem_1.py

@@ -0,0 +1,17 @@
+# Find Missing Number in a sorted array range from 1 to n.
+
+def findMissing(nums):
+    n = len(nums)
+    low,high = 0, n-1
+    while low <= high:
+        mid = low + (high - low)//2
+        curr = nums[mid]
+        if curr == mid + 1:
+            low = mid + 1
+        else:
+            high = mid - 1
+    return low + 1
+
+nums = [1,3,4,5,6,7,8]
+nums = [2]
+print(findMissing(nums))