Warm-up challenge Classwork

.gitignore

@@ -0,0 +1,2 @@
+#Ignoring dir
+.*/

classwork/01/reverse.py

@@ -0,0 +1,10 @@
+# Function to reverse array
+
+def reverse(A):
+    A = A[::-1]
+    return A
+
+
+if __name__ == '__main__':
+    a = [1, 2, 3, 4, 5]
+    print(reverse(a))

classwork/02/sum_target.py

@@ -0,0 +1,19 @@
+def target_sum(arr, target):
+    sum_indices = []
+
+    for i in range(len(arr)):
+        for j in range(i, len(arr) - 1):
+            if arr[i] + arr[j+1] == target:
+                sum_indices = [i, j + 1]
+
+                break
+        else:
+            continue
+        break
+
+    return sum_indices
+
+
+if __name__ == '__main__':
+    print(target_sum([2, 4, 11, 8], 12))
+    print(target_sum([2, 3, 4], 6))

classwork/03/evaluate.py

@@ -0,0 +1,30 @@
+import re
+
+
+def evaluate(S):
+    # Remove all whitespaces in string
+    s = S.replace(' ', '')
+
+    # Split string at operators  into array
+    arr = re.split(r'(\D)', s)
+
+    # Intialize first element of array as result
+    result = int(arr[0])
+
+    # Iterate through the array operating on the numbers depending on operator
+    # and update result
+    for i in range(0, len(arr) - 2, 2):
+
+        if arr[i + 1] == '+':
+            result += int(arr[i + 2])
+
+        else:
+            result -= int(arr[i + 2])
+
+    return result
+
+
+if __name__ == '__main__':
+    s = "8 + 3 + 6 + 2 - 3"
+
+    print(evaluate(s))

classwork/04/singly_linked_list.py

@@ -0,0 +1,89 @@
+# the Node class - contains value and address to next node
+class Node(object):
+    def __init__(self, val):
+        self.val = val
+        self.next = None
+
+    def get_data(self):
+        return self.val
+
+    def set_data(self, val):
+        self.val = val
+
+    def get_next(self):
+        return self.next
+
+    def set_next(self, next):
+        self.next = next
+
+
+# the LinkedList class
+class LinkedList(object):
+    def __init__(self, head=None):
+        self.head = head
+        self.count = 0
+
+    def get_count(self):
+        return self.count
+
+    def insert(self, data):
+        new_node = Node(data)
+        new_node.set_next(self.head)
+        self.head = new_node
+        self.count += 1
+
+    def find(self, val):
+        item = self.head
+        while (item != None):
+            if item.get_data() == val:
+                return item
+            else:
+                item = item.get_next()
+        return None
+
+    def deleteAt(self, idx):
+        if idx > self.count:
+            return
+        if self.head == None:
+            return
+        else:
+            tempIdx = 0
+            node = self.head
+            while tempIdx < idx-1:
+                node = node.get_next()
+                tempIdx += 1
+            node.set_next(node.get_next().get_next())
+            self.count -= 1
+
+    def printList(self):
+        tempnode = self.head
+        while (tempnode != None):
+            print("Node: ", tempnode.get_data())
+            tempnode = tempnode.get_next()
+
+    def sumList(self):
+        tempnode = self.head
+        self.sum = 0
+        while (tempnode != None):
+            self.sum += tempnode.get_data()
+            tempnode = tempnode.get_next()
+        print('Sum of list:', self.sum)
+
+
+
+if __name__ == "__main__":
+    # create a linked list and insert some items
+    itemlist = LinkedList()
+    itemlist.insert(3)
+    itemlist.insert(10)
+    itemlist.insert(1)
+    itemlist.insert(5)
+    itemlist.insert(6)
+
+    #Print the List
+    itemlist.printList()
+
+    #GEt sum
+    itemlist.sumList()
+
+