2.6.2 Binary Search Recursive Method

Divide and Conquer
Binary search Recursive method
Analysis

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Data Structures using C and C++

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[mohammadfaisal]

i wish there was a coding part also. i Have NEVER seen a teacher with this level of understanding in data structures.

[atulgunjal]

Your mastery in converting complicated algorithmic steps into the simple stages is impressive.

[nitiKT]

Bari Sir, hats off to you. I brag to my friends that I was your student and thought me DSA during my engineering and every time I have an interview I make sure I go through some of your videos..

[preethamm.n]

Sir, u are my hero sir
👑God of algorithms 👑
😇🌞😎💻
"Simply in the nptel outdated teachers are teaching the same concept for hours together
And u are awesome sir without missing out any of the concepts u are teaching better than them sir"
As enstien said "if u can't explain in simple, u have to understand well enough"
For the above qoute Ur best example sir
Thank u sir it's helping me a lot
God bless u sir

[mansoorkhattak]

Sir you are hero, superb !! Allah lambi zindagi de :)

[jessesinger]

31/83 videos in, bought your course on data structures. Maybe jumping ahead of myself, but you're amazing at explaining this.

[mohamedatef]

This is, by far the best tutorial for learning binary search I've ever seen.
Many people have sufficient knowledge and skills and they try passing them to others
but a few of them can deliver them in a convenient method like Abdul Bari Does.

[saran]

There is a slight mistake in your algorithm if(l==h) will throw you a stackoverflow error instead you should use

[abhilashpatel]

Being from non cs background, it was very difficult for me to find time complexity of a algorithm. Your recurrence relation series has helped me alot.

[Swansylinks]

You're so unique, I failed algorithm because I didn't understand it when my lecturer taught me. I am sure I will scatter my Saturday's exam curtesy of you Dr Abdul Bari.

[mustafamahmoudahmed]

Thanks for this helpful playlist, you are the best.

I tried to implement the algorithm as it is in the video, it didn't work except for values already in the array.

My recommendation:
1- remove the if block
2- Modify the else block to be "if (l <= h)"
3- Add else block which returns -1 in case "l > h"

Here is my implementation in C++:

int BinSearch(int l, int h, int key, vector<int> arr) {
int mid;
if (l <= h) {
mid = (l + h) / 2;
if (key == arr[mid])
return mid;
else if (key < arr[mid])
return BinSearch(l, mid - 1, key, arr);
else
return BinSearch(mid + 1, h, key, arr);
}
else
return -1;
}

Finally, I want to thank you for your effort in this series which really helps me to learn from scratch.

[practicemail]

I'm a non-cs background student and even i can understand such simple explanation. Hats off to you sir for your contribution sir.

[protek]

I never understood recursion, but after watching this video I know all of it
thanks, Abdul sir!

[StefanoCocomazzi]

I can only shay Thank You. I Just passed my algorithm exam with honors.
Thank you, thank you and again thank you

[backpropagated]

Thank you for these videos Abdul Bari. I normally struggle to learn from videos, but your concisesness helps so much. I know that my focus won't be wasted, so I can listen intently for the full video.

[subramaniyanvg]

Sir you should be guiding students for companies like google and amazon. Also please write a book on Data Structures definitely I will buy.

[AbdullahSiddiqui]

now i am clear you teach it better then, even our university teacher.

[khale-d]

this also is a good algorithm:
def RBinarySearch(arr, value, l = 0, h = 0):
if(l>h):
return -1
mid = int((l+h) /2)
if(arr[mid] == value):
return mid
elif (value > arr[mid]):
l = mid+1
else :
h = mid-1
return RBinarySearch(arr, value, l, h)

arr = [1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29]

print(RBinarySearch(arr, 25, 0, len(arr)-1))

[zureka]

Sir in your recursive code, you didn't give a condition for when the element can't be found, i.e. you have to give a condition that when l>h return -1. Other than that amazing lectures

[evash]

cannot express my gratitude. Thank you Mr Abdul - all of your videos are priceless! you're a legend. Thank you for helping to improve