Completed 3 Questions

Q1/solution.py

@@ -1 +1,22 @@
-## Add code below with answer clearly stated
+def get_factorial(number):
+    """Returns Factorial of number, with trailing zeros removed because they don't contribute to the sum"""
+    fact = 1
+    for num in range(2, number + 1):
+        fact *= num
+        if num % 5 == 0:
+            while fact % 10 == 0:
+                fact //= 10
+    return fact
+
+
+def digit_sum_for(number):
+    """Returns the sum of the all digits of a number"""
+    total = 0
+    for digit in str(number):
+        total += int(digit)
+    return total
+
+
+factorial = get_factorial(100)
+digit_sum = digit_sum_for(factorial)
+print(digit_sum)

Q2/solution.py

@@ -1,8 +1,26 @@
+from typing import Optional
+
+
 # Definition for singly-linked list.
-# class ListNode:
-#     def __init__(self, val=0, next=None):
-#         self.val = val
-#         self.next = next
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
 class Solution:
     def removeNthFromEnd(self, head: Optional[ListNode], n: int) -> Optional[ListNode]:
+        fast = slow = head
+        for index in range(n):
+            fast = fast.next
+
+        if not fast:
+            return head.next
+
+        while fast.next:
+            fast = fast.next
+            slow = slow.next
+
+        slow.next = slow.next.next
+        return head
 

Q3/solution.py

@@ -1,3 +1,33 @@
+from typing import List
+
+
 class Solution:
     def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:
-
+        length = len(nums1) + len(nums2)
+        if length % 2 == 1:   # if merged array has odd length return middle element
+            return self.findMedian(nums1, nums2, length // 2)
+        else:   # if even length then return (middle + middle - 1)/2
+            return (self.findMedian(nums1, nums2, length // 2) + self.findMedian(nums1, nums2, length // 2 - 1)) / 2
+
+    def findMedian(self, nums1, nums2, mid):
+        if not nums1:   # if first array is empty just consider second array
+            return nums2[mid]
+        if not nums2:
+            return nums1[mid]
+        i_nums1, i_nums2 = len(nums1) // 2, len(nums2) // 2
+        m_nums1, m_nums2 = nums1[i_nums1], nums2[i_nums2]
+
+        # if mid is bigger than the sum of nums1 and nums2's median indices
+        if i_nums1 + i_nums2 < mid:
+            # if nums1's median is bigger than nums2's, nums2's first half doesn't include mid
+            if m_nums1 > m_nums2:
+                return self.findMedian(nums1, nums2[i_nums2 + 1:], mid - i_nums2 - 1)
+            else:
+                return self.findMedian(nums1[i_nums1 + 1:], nums2, mid - i_nums1 - 1)
+        # when mid is smaller than the sum of nums1 and nums2's indices
+        else:
+            # if nums1's median is bigger than nums2's, nums1's second half doesn't include mid
+            if m_nums1 > m_nums2:
+                return self.findMedian(nums1[:i_nums1], nums2, mid)
+            else:
+                return self.findMedian(nums1, nums2[:i_nums2], mid)