Complete Summary and Solutions for Searching – NCERT Class XII Computer Science, Chapter 6 – Linear Search, Binary Search, Hashing, Algorithms, Questions, Answers

Comprehensive summary and explanation of Chapter 6 'Searching' from the Computer Science textbook for Class XII, covering the concept of searching, linear search algorithm and its working, binary search algorithm for sorted lists, hashing techniques for efficient search, collision, and collision resolution—along with all NCERT questions, answers, and exercises for practical understanding.

Updated: 2 days ago

Categories: NCERT, Class XII, Computer Science, Chapter 6, Searching, Linear Search, Binary Search, Hashing, Summary, Questions, Answers, Programming, Comprehension
Tags: Searching, Linear Search, Binary Search, Hashing, Collision, Algorithms, NCERT, Class 12, Computer Science, Summary, Explanation, Questions, Answers, Programming, Chapter 6
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Searching in Python - Class 12 Computer Science Chapter 6 Ultimate Study Guide 2025

Searching in Python

Chapter 6: Computer Science - Ultimate Study Guide | NCERT Class 12 Notes, Questions, Code Examples & Quiz 2025

Full Chapter Summary & Detailed Notes - Searching Class 12 NCERT

Overview & Key Concepts

  • Chapter Goal: Understand searching techniques: Linear (sequential), Binary (divide-conquer on sorted), Hashing (direct access via function). Exam Focus: Algorithms 6.1-6.2, Programs 6-1 to 6-3, Tables 6.1-6.10; 2025 Updates: Efficiency in big data. Fun Fact: Brian Kernighan quote on computing ties to search ops. Core Idea: Efficient retrieval from collections; from O(n) linear to O(1) hash. Real-World: Database queries. Expanded: All subtopics point-wise with evidence (e.g., Table 6.2 comparisons), examples (e.g., key=17 in [8,-4,7,17...]), debates (e.g., sorted cost vs binary speed).
  • Wider Scope: From unsorted small lists to hashed tables; sources: Algorithms, programs, tables/figures.
  • Expanded Content: Include time complexity (linear O(n), binary O(log n), hash O(1)); point-wise for recall; add 2025 relevance like parallel search.

Introduction

  • Searching Defined: Locate key in collection; return presence/position. Essential for data retrieval.
  • Importance: Algorithms need varied search methods; affects efficiency.
  • Example: Home items vs computer data on demand.
  • Practical Difficulties: Unordered → slow; Solutions: Choose method by list size/order.
  • Expanded: Evidence: Quote on computing impact; debates: Search vs sort trade-off; real: Search engines.
Conceptual Diagram: Search Flow

Flow: Collection → Key Input → Compare/Compute Index → Found/Not Found → Position/None. Ties to Algorithm 6.1.

Why This Guide Stands Out

Comprehensive: All methods point-wise, program integrations; 2025 with big-O analysis, processes for real code.

Linear Search

  • Overview: Sequential check from start; O(n) worst/best variable. For small/unsorted lists.
  • Algorithm 6.1: Index=0; while
  • Example 6.1: [8,-4,7,17,0,2,19] key=17 → 4 comparisons (Table 6.2).
  • Best/Worst: First elem (1 comp), last/not found (n comps) (Tables 6.3-6.4).
  • Program 6-1: Input list/key; return pos/None (Output: 23 at 2).
  • Expanded: Evidence: Activity 6.1 (key=12 → 8 comps); real: Unsorted arrays.
IndexValue
08
1-4
27
317

Binary Search

  • Overview: Divide sorted list; compare mid; halve search. O(log n).
  • Pre-req: Sorted ascending/descending/alphabetical.
  • Process: Mid=(first+last)//2; if match return; >key last=mid-1;
  • Example 6.2: [2,3,5,7,10,11,12,17...] key=17 → 1 iter (mid=7, match Table 6.6).
  • Max Iter: Key=2 → 4 iters (Table 6.7, halves 15→7→3→1).
  • Program 6-2: Input sorted list/key; return index/-1 (Output: 4 at 3; not found).
  • Expanded: Evidence: Activity 6.3 (key=7 → 2 iters); debates: Sort overhead.

Search by Hashing

  • Overview: Hash function → index; O(1) lookup. Hash table > list size possible.
  • Hash Function: Remainder (elem % size); e.g., %10.
  • Example: List [34,16,2,93,80,77,51] → Table 6.10 (80 at 0, etc.).
  • Search: Compute index; compare once (Program 6-3, Output: 16 at 7).
  • Collision: Same hash (e.g., 16%10=6, 26%10=6); resolve beyond scope.
  • Expanded: Evidence: Perfect hash no collision; real: Dictionaries.

Summary & Exercise

  • Key Takeaways: Linear simple/slow; Binary fast/sorted; Hash constant/direct. Choose by scenario.
  • Exercise Tease: Compare comps (Ex1: positions); code linear/binary (Ex3-4); hash table (Ex8).