Algorithm for Finding Sub-arrays

Study Notes

Problem Definition

Input consists of a 1-D array containing 10 positive integers.
The objective is to find all sub-arrays that sum to 15.

Algorithm

Initialize p as 18 (binary representation: 00001111).
Perform left shift operations resulting in p = 60 (binary: 00111100).
Conduct right shift operations yielding p = 3.
Confirm that p equals 15 divided by (2²).

XOR Operations for Swapping

To swap two values a and b:
- a = a ^ b
- b = a ^ b
- a = a ^ b

Ternary Conditional Operator

Syntax: expr1 ? expr2 : expr3
Meaning: If expr1 is true, evaluate expr2; otherwise, evaluate expr3.

Switch Case Structure

Utilizes a switch statement to evaluate a variable (e.g., grade).
Each case triggers a specific output, with a default to handle any unexpected values.

Insertion Sort Algorithm

Iteratively insert elements into their correct position within a sorted portion of the array.

Pointers and Memory Management

int arr; allows arr to reference the first element of an array.
arr[i] accesses the ith element using pointer arithmetic.
&arr indicates the address of the entire array.

Array of Pointers

Declared as int *a; which can point to elements of arrays.
Enables manipulation of array values through pointers.

Finding Minimum of Two Numbers

Use bitwise operations to determine the minimum value:
r = y^((nry) & -(ncy))

Null Statement Usage

Example code illustrates using a null statement in an if condition that could produce warnings.

Type Casting

Converting one data type to another.
Implicit casting occurs automatically while explicit casting is done manually.

Array Declaration and Usage

Declare arrays like int arr[] = {5, 4, 19, 2};.
Multidimensional arrays like int matrix[a][b]; need rows and columns defined.

Sorting Methods: Row vs. Column Major Order

Row Major Order: Fills memory row by row.
Column Major Order: Fills memory column by column.
C uses Row Major Order for multidimensional arrays, improving memory access efficiency with loops.

Function Syntax and Usage

Define functions with a return type and parameters: datatype functionName(parameters).
Example of a swap function that incorrectly swaps two numbers is provided.

Memory Allocation Types

Static Memory Allocation: Defined at compile time, memory size cannot change.
Dynamic Memory Allocation: Occurs at runtime, allowing flexible memory usage.

Dynamic Memory Allocation Functions

malloc() function allocates memory dynamically and returns a pointer.
On success, it yields the address of allocated memory; on failure, it returns NULL.

Example of Dynamic Memory Allocation with Malloc

Sample code to demonstrate allocating memory for an integer array using malloc().

Description

This quiz explores algorithms for identifying all sub-arrays within a one-dimensional array of ten positive integers that sum up to 15. It covers topics such as bit manipulation, conditional expressions, and switch statements in programming. Test your understanding of these concepts with practical examples!