JavaScript arrays

JavaScript arrays ek mast aur versatile tool hai jo tumhare DSA (Data Structures and Algorithms) mein bahut kaam aate hain! 📚💻

Ab samjho DSA ke context mein, arrays kaise kaam karte hain aur kya-kya operations perform ho sakte hain. 🚀

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Array Basics in JavaScript

JavaScript mein, arrays ekdum flexible hote hain:

• Tum different types ke data ek hi array mein rakh sakte ho. 🧃🍕💰
  Example:

  let arr = [10, "hello", true, 42];
  

• Tum dynamic size wale arrays bana sakte ho. Na koi size batana, na koi tension! 🌀

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Common Operations in JavaScript Arrays (DSA Style)

1️⃣ Traversal (Array ke elements ko access karna)

• Traversal ka matlab hai ek-ek karke har element ko dekhna. 👀
• Example:

  let arr = [10, 20, 30, 40];
  for (let i = 0; i < arr.length; i++) {
    console.log(arr[i]); // Output: 10, 20, 30, 40
  }
  

  👉 Big O Time Complexity: O(n)
  Tumhe (n) elements check karne padenge.

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2️⃣ Searching (Koi particular value dhoondhna)

• Tum linear search use karte ho to ek value dhoondhne ke liye. Agar array sorted hai, to binary search use kar sakte ho! 🔍

• Example (Linear Search):

  let arr = [10, 20, 30, 40];
  let target = 30;
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] === target) {
      console.log("Found at index: " + i); // Output: Found at index: 2
    }
  }
  

  👉 Time Complexity:

  • Linear Search: O(n)
  • Binary Search (sorted arrays): O(log n)

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3️⃣ Insertion (Naya element add karna)

• End me add karna:
  Easy peasy! Bas .push() use karo.
  Example:

  let arr = [10, 20, 30];
  arr.push(40); // [10, 20, 30, 40]
  

  👉 Time Complexity: O(1)

• Shuru ya beech me add karna:
  Yaha tumhe baaki elements ko shift karna padta hai. 😥
  Example:

  let arr = [10, 20, 30];
  arr.splice(1, 0, 15); // [10, 15, 20, 30]
  

  👉 Time Complexity: O(n)

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4️⃣ Deletion (Element ko hataana)

• End se delete karna:
  Bas .pop() use karo.
  Example:

  let arr = [10, 20, 30];
  arr.pop(); // [10, 20]
  

  👉 Time Complexity: O(1)

• Shuru ya beech se delete karna:
  Baaki elements ko shift karna padta hai.
  Example:

  let arr = [10, 20, 30];
  arr.splice(1, 1); // [10, 30]
  

  👉 Time Complexity: O(n)

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DSA ke Context mein Common Problems

1. Reverse an Array 🌀

   let arr = [1, 2, 3, 4];
   arr.reverse();
   console.log(arr); // Output: [4, 3, 2, 1]
   

2. Find Maximum and Minimum in Array 📈📉

   let arr = [10, 20, 5, 15];
   let max = Math.max(...arr);
   let min = Math.min(...arr);
   console.log(max, min); // Output: 20, 5
   

3. Sorting an Array 🔢

   let arr = [40, 10, 30, 20];
   arr.sort((a, b) => a - b); // Ascending order
   console.log(arr); // Output: [10, 20, 30, 40]
   

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Big O Table for JavaScript Array Operations

Operation	Best Case	Worst Case	Description
Access	O(1)	O(1)	Direct index se value access.
Search	O(1)	O(n)	Linear search ke liye.
Insert (end)	O(1)	O(1)	End me value add karna.
Insert (start/any)	O(1)	O(n)	Baaki elements ko shift karna.
Delete (end)	O(1)	O(1)	End se value delete karna.
Delete (start/any)	O(1)	O(n)	Baaki elements ko shift karna.

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Ek Chhoti Kahani:

Socho tumhari ek grocery list hai:
["Apples", "Bananas", "Oranges"] 🍎🍌🍊

• Access: Bol do arr[1] aur “Bananas” turant mil jayenge! 🏎️
• Add: Tum .push("Grapes") karoge to list ke end me Grapes aa jayenge. 🍇
• Delete: Agar tum “Apples” hatana chahte ho, to .splice(0, 1) karna padega.

JavaScript arrays flexible aur powerful hote hain, but bade data ke liye optimize karna zaruri hai. ✨