graph algo added

Author: shiningflash

Diff for: Advance-Data-Structure/PYTHON/graph/dfs.py

@@ -0,0 +1,29 @@
+"""
+DFS
+
+TC: O(V+E)
+SC: O(V)
+"""
+
+
+def dfs(graph, visited, node):
+    if node in visited:
+        return
+
+    print(node)
+    visited.add(node)
+    for neighbour in graph[node]:
+        dfs(graph, visited, neighbour)
+
+
+if __name__ == '__main__':
+    graph = {
+        '5': ['3', '7'],
+        '3': ['2', '4'],
+        '7': ['8'],
+        '2': [],
+        '4': ['8'],
+        '8': []
+    }
+    visited = set()
+    dfs(graph, visited, '5')

Diff for: Advance-Data-Structure/PYTHON/linked_list.py

@@ -0,0 +1,96 @@
+class Node:
+    def __init__(self, data=None):
+        self.data = data
+        self.next = None
+
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    def insertAtBeginning(self, data):
+        new_node = Node(data)
+        new_node.next = self.head
+        self.head = new_node
+
+    def insertAtEnd(self, data):
+        new_node = Node(data)
+
+        if not self.head:
+            self.head = new_node
+            return
+
+        curr = self.head
+        while curr.next:
+            curr = curr.next
+
+        curr.next = new_node
+
+    def search(self, data):
+        if not self.head:
+            print('List is empty!')
+
+        curr = self.head
+        while curr:
+            if curr.data == data:
+                return True
+            curr = curr.next
+        return False
+
+    def deleteNode(self, position):
+        if not self.head:
+            return
+
+        curr = self.head
+
+        if position == 0:
+            self.head = curr.next
+            curr = None
+            return
+
+        for i in range(position-1):
+            curr = curr.next
+            if not curr:
+                return
+
+        if not curr.next:
+            return
+
+        next_node = curr.next.next
+        curr.next = None
+        curr.next = next_node
+
+    def printList(self):
+        if not self.head:
+            print('List is empty!')
+            return
+
+        curr = self.head
+        while curr:
+            print(curr.data, end=' --> ')
+            curr = curr.next
+        print()
+
+
+if __name__ == '__main__':
+    llist = LinkedList()
+    print(llist.search(1))
+    llist.printList()
+    llist.insertAtBeginning(1)
+    print(llist.search(1))
+    print(llist.search(2))
+    llist.printList()
+    llist.insertAtBeginning(3)
+    llist.insertAtBeginning(7)
+    llist.printList()
+    llist.insertAtEnd(-1)
+    llist.insertAtEnd(-17)
+    llist.printList()
+    llist.deleteNode(0)
+    llist.printList()
+    llist.deleteNode(7)
+    llist.printList()
+    llist.deleteNode(2)
+    llist.printList()
+    llist.deleteNode(2)
+    llist.printList()

Diff for: Number-Theory/Python/sieve.py

@@ -0,0 +1,24 @@
+import math
+
+MX = 105
+
+
+def sieve(isPrime):
+    isPrime[0] = isPrime[1] = False
+    for i in range(2, int(math.sqrt(MX))):
+        if isPrime[i]:
+            for j in range(2*i, MX, i):
+                isPrime[j] = False
+
+
+def printPrime(isPrime):
+    for i in range(MX):
+        if isPrime[i]:
+            print(i, end=" ")
+    print()
+
+
+if __name__ == '__main__':
+    isPrime = [True for _ in range(MX)]
+    sieve(isPrime)
+    printPrime(isPrime)