Final Commit for Doubly Linked List

day29/C++/binary_search.cpp

@@ -1,55 +1,59 @@
-/*
-* @author : imkaka
-* @date   : 31/1/2019
-*/
-
-#include<iostream>
-#include<cstdio>
+/**
+ * @author: Karthick < karthikn2099@gmail.com >
+ * @github: https://github.com/karthikn2098
+ * @date: 31/01/2018
+ */
 
+#include <iostream>
 using namespace std;
 
-int binary_search_itr(int arr[], int size, int val){
-    int l = 0, r = size-1;
-    int mid = (l + r) / 2;
+/** @desc: splits the array into two sections at each step, then checks the element in the desired one.
+  * @param: array , key (to be found), size of the array.
+  * @return: index of key if present , -1 otherwise.
+  * @TimeComplexity: O( logn )   < n = size of the array >
+  */
+int Binary_search(int arr[] , int key, int N) {
+
+    int low = 0 , high = N-1 , mid;
+
+    while(low <= high) {
 
-    while(arr[mid] != val && l <= r){
-        if(val < arr[mid]){
-            r = mid - 1;
+        mid = low + (high - low) / 2;   //like (low + high)/2 but efficient.
+
+        if(key == arr[mid]) {
+            return mid;
         }
-        else{
-            l = mid +1;
+        else if( key > arr[mid] ) {
+            low = mid + 1;
+        }
+        else {
+            high = mid - 1;
         }
-
-        mid = (l + r) / 2;
     }
 
-    if(arr[mid] == val)
-        return mid;
-
     return -1;
 }
 
-int binary_search_rec(int arr[], int left, int right, int val){
-    if(right >= left){
+int main(void) {
 
-        int mid = left + (right - left) / 2;
+    int arr[] = { 1, 3, 5, 7, 8, 9, 100, 234, 788, 899 };
 
-        if(arr[mid] == val) return mid;
+    int sizeOfArray = sizeof(arr) / sizeof(arr[0]);
 
-        if(arr[mid] > val)
-            return binary_search_rec(arr, left, mid-1, val);
-        return binary_search_rec(arr, mid+1, right, val);
-    }
+    cout << "\nBinary_search(arr , 100) = " << Binary_search(arr, 100, sizeOfArray ) << endl;
 
-    return -1;
-}
-
-int main(){
+    cout << "\nBinary_search(arr , 1000) = " << Binary_search(arr, 1000, sizeOfArray ) << endl;
 
-    int arr[] = {1, 2, 3, 6, 9, 15, 16, 14};
-    int val = 9;
-    int size = sizeof(arr)/sizeof(arr[0]);
-    cout << "Iterative: " << binary_search_itr(arr, size, val) << endl;
-    cout << "Recursive: " << binary_search_rec(arr, 0, size-1, val) << endl;
     return 0;
 }
+
+/*
+---------------
+ Sample Output
+---------------
+
+Binary_search(arr , 100) = 6
+
+Binary_search(arr , 1000) = -1
+
+*/

day48/Python/DLL.py

@@ -0,0 +1,84 @@
+"""
+@author: Abhishek Reddy
+@date: 2/25/2019
+"""
+
+import gc
+
+
+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+        self.prev = None
+
+
+class DLL:
+    def __init__(self):
+        self.head = None
+
+    def push(self, data):
+        new_node = Node(data)
+        new_node.next = self.head
+        new_node.prev = None
+        if self.head is not None:
+            self.head.prev = new_node
+        self.head = new_node
+
+    def pushAfter(self, prevnode, data):
+        if prevnode is None:
+            return
+        new_node = Node(data)
+        new_node.next = prevnode.next
+        prevnode.next = new_node
+        new_node.prev = prevnode
+        if new_node.next is not None:
+            new_node.next.prev = new_node
+
+    def append(self, data):
+        new_node = Node(data)
+        if self.head is None:
+            new_node.prev = None
+            new_node.next = None
+            self.head = new_node
+            return
+        else:
+            tmp = self.head
+            while tmp.next is not None:
+                tmp = tmp.next
+            tmp.next = new_node
+            new_node.prev = tmp
+            new_node.next = None
+
+    def popAtPos(self, prevnode):
+        if self.head is None or prevnode is None:
+            return
+        if self.head == prevnode:
+            self.head = prevnode.next
+        if prevnode.next is not None:
+            prevnode.next.prev = prevnode.prev
+        if prevnode.prev is not None:
+            prevnode.prev.next = prevnode.next
+        gc.collect()
+
+    def popFirst(self):
+        tmp = self.head
+        self.head = self.head.next
+        self.head.prev = None
+        tmp.next = None
+    def popEnd(self):
+        tmp = self.head
+        while tmp.next is not None:
+            tmp = tmp.next
+        tmp.prev.next = None
+        tmp.prev = None
+
+    def printList(self):
+        temp = self.head
+        while temp is not None:
+            print(temp.data)
+            temp = temp.next
+
+
+d = DLL()
+