DSA collections

1). Remove all adjacent duplicate character.

abbac: Input

ac : Output

Use stack.

2). find nth element of Febnocci number.

Use recursion

1 1 2 3 5 8 13 21..

3).print inverted Tree.

4). Police and Thief : 

How many max thieves can be cought?

(P T T P P P T P T P)

One P can catch only one Thief.

One police can catch a thief at a distance K.

K=1.

5).  Evaluate reverse police notation.

Use stack to push operand and then pop and do operations if operand is found.

6). Find and delete nth node from the end in the singly Linked List.

7). Merge two sorted Arrays.

System Programming materials

http://csapp.cs.cmu.edu/3e/students.html

http://beej.us/guide/bggdb/

Dennis M. Ritchie On Developement of C language:
http://csapp.cs.cmu.edu/3e/docs/chistory.html

LTE Interview questions

Here are some of the basic question that are asked in LTE interview:

1. Questions related to cat-m like ack/Nack in UL/DL, half duplex
2. Pucch and pusch can go in same tti?
3. Who triggers handover
4. Cell reselection how it happens
5. Can intracell handover happens
6. Handovers scenarios
7. Handover types in LTE, What is difference between X2 and S1 HO?
8. Who triggers handover
9. Interface between different entity
10. Turbo coading and rate matching 
11. How will you design interface between two modules?
12. Questions related to cat-m like ack/Nack in UL/DL, half duplex
13. Pucch and pusch can go in same tti?
14. Cell reselection how it happens
15. Can intracell handover happens
16. TA update
17. CAT-M UEs
18. Rach procedure
19. Compelete attach flow
20. Pucch formats
21. Catm DCI formats
22. Channels added n removed in catm
23. Cell reselection how it happena
24. Can intracell handover happens
25. Tell us about LTE Frame Structure?
26. What is Subcarrier Bandwidth in LTE?
27. What is BLER? What’s Target value?
28. How to investigate low throughput?
29. What are important LTE KPIs ?
30. How can we calculate LTE DL/UL throughput?
31. What Maximum LTE throughput can be achieved in the field?
32. What is difference between HO , Redirection, Cell Selection / Re-Selection?
33. What is RRC Reconfiguration?
34. What is Difference between MIB and SIB?
35. How many types of SIBs are available in LTE?
36. What does SIB1/SIB2/ … /SIB13 do?
37. On which channels SIBs are transmitted?
38. Which SIBs are essential?
39. Message flow during LTE Call?
40. Can you tell us about Prach/PCI/Pusch/Pucch Planning?
41. Explain Handover signalling messages?
42. Explain Events measurements in LTE
43. Which event trigger during the reselection from LTE to 3G and vice versa
44. What is ANR? types of ANR? Which one is better?
45. What is QCI?
46. What is LTE modulation?AMC?
47. What is TM? TM1? TM2? TM3? TM4?
48. Mapping of MIB and SIB messages?
49. Explain SIB messages?
50. What Message will be observed on layer-3 During handover stage?
51. Which channel carries CQI information to enodB?
52. What other info PUCCH carries?
53. What is DRX?
54. What is the Location of PUCCH in the UL Spectrum?
55. CS Fall back criteria and event, Explain CSFallback signalling?
56. Explain PCI (Physical Cell id) 

Frequently asked Operating System questions

Below are some of the important subjective questions in Operating system.

Explain Compiler/Linker/Loader
What is semaphore and how its different from Mutex, Where to use what.
What is Pthread, How to implement threads, Conditional variables etc.
User Level thread Vs Kernel Level thread

Frequently asked C Programming Questions

Below are the list of some of the questions:

CFAQ:
http://c-faq.com



Some of the good links for Bit Manipulations:
1).  Check if the number is power of two.

If we subtract 1 from a power of 2 what we get is 1s till the last unset bit and if we apply Bitwise AND operator we should get only zeros.

/* Function to check if x is power of 2*/

bool isPowerOfTwo (int x)

{

  /* First x in the below expression is for the case when x is 0 */

  return x && (!(x&(x-1)));

}

2). Check if he number is even of Add using Bitwise operator:

The idea is to check whether the last bit of the number is set or not. If the last bit is set then the number is odd, otherwise even. 

A). bitwise XOR Operation of the Number by 1 increment the value of the number by 1 if the number is even otherwise it decrements the value of the number by 1 if the value is odd.

// Returns true if n is even, else odd

bool isEven(int n)

{

 

    // n^1 is n+1, then even, else odd

    if (n ^ 1 == n + 1)

        return true;

    else

        return false;

}

B).  Biwise And

// Returns true if n is even, else odd

bool isEven(int n)

{

    // n&1 is 1, then odd, else even

    return (!(n & 1));

}

  

c). W know bitwise OR Operation of the Number by 1 increment

the value of the number by 1 if the number is even otherwise

it will remain unchanged.

// Returns true if n is even, else odd

bool isEven(int n)

{

 

    // n|1 is greater than n, then even, else odd

    if ((n | 1) > n)

        return true;

    else

        return false;

} 

3). // C program to check if k-th bit

// of a given number is set or not

#include <stdio.h>

 

void isKthBitSet(int n, int k)

{

    if (n & (1 << (k - 1)))

        printf("SET");

    else

        printf("NOT SET");

}

1).Bit Twiddling Hacks
2).Bitwise Operators from GeekforGeeks

3). 

Strings

Pointers

1. Implementing system calls by yourself (sizeof, strcpy, strcmp etc)
2. Implement your own sizeof and explain
3. 
   
4. 
   

Function Pointers

Structures/Unions/Bit fields/ Structure padding

Memory allocations and APIs (Malloc/calloc/realloc/heap)

 

1. What is the point of using malloc(0)?

Various Keyword (Static, Volatile etc)

1. Can static variables be declared in a header file?
2. Can a variable be both const and volatile?

Make Files

Libraries (Static/Dynamic)

GCC Flags




Some  popular questions:

1. Difference between malloc and new?
2. How will you design interface between two modules?
3. Where variables sits In memory
4. Diff between Vector and list .
5. Volatile keyword
6. Diff between Structure and union 
7. How to get size for union and structure
8. Memory allocation in c
9. Heap or variable which memory is fast
10. Diff between link list and and vector
11. Bit field, how these stored in memory
12. Big endian and little endian
13. If 1000 of integer linklist and array is present which would be faster and why
14. Synchronisation in thread
15. Diff in mutex and binary semaphore
16. C memory management
17. C Storage class
18. Gdb
19. Binary search
20. Multi dimensional array
21. IPC mechanism
22. Which storage class is fast
23. Write your own strtok function where each call return one token separated by delimiter  passed in the string passed. 
24. Reverse string in place. 
25. What are different gcc compiler options to secure your code. 
26. How malloc works behind the scene.
27. How can you protect the same. 
28. What is memory corruption. Different types. 
29. How printf works and write your own printf which can print all basic data type of c. 
30. What is the security issue with printf. 
31. Difference between strlcpy and strncpy. What is the security issue with this. 
32. Check for Balanced parenthesis.

     - using Stack method how you will implement stack and what are different ways. 

     -above algo using lot of memory. now implement same using minimal use of memory.