Update kth-missing-positive-number.py

Author: kamyu104

Python/kth-missing-positive-number.py

@@ -9,13 +9,13 @@ def findKthPositive(self, arr, k):
         :rtype: int
         """
         def check(arr, k, x):
-            return arr[x]-(x+1) >= k
+            return arr[x]-(x+1) < k
 
         left, right = 0, len(arr)-1
         while left <= right:
             mid = left + (right-left)//2
-            if check(arr, k, mid):
+            if not check(arr, k, mid):
                 right = mid-1
             else:
                 left = mid+1
-        return left+k  # arr[left-1] + (k-(arr[left-1]-((left-1)+1))) if left else k
+        return right+1+k  # arr[right] + (k-(arr[right]-(right+1))) if right >= 0 else k