a few problems at a time

Author: OfficialCodeVoyage

1_TwoSum/solution1.py

@@ -0,0 +1,29 @@
+# Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
+#
+# You may assume that each input would have exactly one solution, and you may not use the same element twice.
+#
+# You can return the answer in any order.
+from typing import Tuple, Any
+
+nums = [2,7,11,15]
+target = 9
+
+def sum(nums, target) -> tuple[Any, Any]:
+
+    # for i in range(len(nums)):
+    #     for j in range(i+1, len(nums)):
+    #         if nums[i] + nums[j] == target:
+    #             return i, j
+    #
+    #     return -1, -1
+
+    dict = {}
+
+    for i, n in enumerate(nums):
+        complement = target - n
+        if complement in dict:
+            return dict[complement], i
+        dict[n] = i
+
+print(sum(nums, target))
+

724_ Find Pivot Index/solution.py

@@ -0,0 +1,31 @@
+# Given an array of integers nums, calculate the pivot index of this array.
+#
+# The pivot index is the index where the sum of all the numbers strictly to the left of the index is equal to the sum of all the numbers strictly to the index's right.
+#
+# If the index is on the left edge of the array, then the left sum is 0 because there are no elements to the left. This also applies to the right edge of the array.
+#
+# Return the leftmost pivot index. If no such index exists, return -1.
+
+
+nums = [1,7,3,6,5,6]
+
+def pivot(nums) -> int:
+    l, r = 0, len(nums) - 1
+    l1, r1 = nums[l], nums[r]
+
+    while l < r:
+        if l1 < r1:
+            l += 1
+            l1 += nums[l]
+        else:
+            r -= 1
+            r1 += nums[r]
+
+
+    if l1 == r1:
+        return l
+
+    return -1
+
+
+print(pivot(nums))

linked_list.py

@@ -0,0 +1,29 @@
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None  # Reference to the next node
+# LinkedList class manages the nodes and operations of the linked list
+class LinkedList:
+    def __init__(self):
+        self.head = None  # Initialize an empty linked list
+    def append(self, data):
+        new_node = Node(data)
+        if not self.head:
+            self.head = new_node
+            return
+        last_node = self.head
+        while last_node.next:
+            last_node = last_node.next
+        last_node.next = new_node
+    def print_list(self):
+        current_node = self.head
+        while current_node:
+            print(current_node.data, end=" -> ")
+            current_node = current_node.next
+        print("None")
+# Example usage:
+llist = LinkedList()
+llist.append(1)
+llist.append(2)
+llist.append(3)
+llist.print_list()

pol_with_x.py

@@ -0,0 +1,28 @@
+# Given a string with "?", return a palindrome if possible. EX: ?ab?b returns babab
+
+string = "?ab??b"
+
+def checkpol(string) -> str:
+    answer_list = [i for i in string]
+
+    if len(answer_list) % 2 != 0:
+        return "Not a palindrome"
+
+    l, r = 0, len(answer_list) - 1
+
+    while l < r:
+        if answer_list[l] == "?":
+            answer_list[l] = answer_list[r]
+        elif answer_list[r] == "?":
+            answer_list[r] = answer_list[l]
+        l += 1
+        r -= 1
+
+    answer_string = ""
+
+    for i in answer_list:
+        answer_string += i
+
+    return answer_string
+
+print(checkpol(string))