SDE - 1

1. Implement stack, push opening brackets in stack and pop closing brackets of same type ( & ), [ & ] , { & }
2. If stack at end is empty, it's valid else invalid

Step 1: Identify Zero Positions

Traverse the matrix and mark the rows and columns where zeros are present. You can use additional data structures to store this information.
Step 2: Set Zeros

Iterate through the matrix again.
For each cell, if its corresponding row or column was marked in Step 1, set the cell value to zero.
Step 3: Optimized Solution without Extra Space

Instead of using extra space, you can use the first row and the first column to store information about whether the corresponding row or column should be zeroed.
Use separate variables to track whether the first row and the first column should be zeroed.
Detailed Steps:

Initialize Flags:

Initialize two flags, zeroFirstRow and zeroFirstColumn, to track whether the first row and first column should be zeroed.
Scan First Row and Column:

Scan the first row and first column separately.
If you find any zero in the first row, set zeroFirstRow to true.
If you find any zero in the first column, set zeroFirstColumn to true.
Mark Zero Positions:

Iterate through the rest of the matrix.
If a zero is found at position (i, j), set matrix[i][0] = 0 and matrix[0][j] = 0 to mark that the corresponding row and column should be zeroed.
Set Zeros Based on Marks:

Iterate through the matrix again (excluding the first row and first column).
If matrix[i][0] == 0 or matrix[0][j] == 0, set matrix[i][j] = 0.
Zero First Row and Column if Necessary:

If zeroFirstRow is true, set all elements in the first row to zero.
If zeroFirstColumn is true, set all elements in the first column to zero.

USE DP Approch

Eg 
str = "ababc"

The longest palindromic substring of "ababc" is "aba", since "aba" is a palindrome and it is the longest substring of length 3 which is a palindrome. 

There is another palindromic substring of length 3 is "bab". Since the starting index of "aba" is less than "bab", so "aba" is the answer.

Thrashing:
Thrashing refers to the state in computing where excessive paging or swapping of data between the main memory and secondary storage occurs, severely degrading system performance. This situation arises when the system lacks sufficient physical memory to support its workload, leading to a constant, inefficient swapping of pages between the main memory and the disk.

Multithreaded Programming:
Multithreaded programming involves the simultaneous execution of multiple threads within a program. This approach aims to enhance performance and responsiveness by allowing different threads to execute independently. Threads share the same resources, such as memory space, but run concurrently, enabling parallelism. This can lead to improved overall system efficiency. Multithreaded programming is beneficial for tasks like parallel computation, managing asynchronous operations, and optimizing resource utilization in systems with multiple processors or cores.

Virtual Memory:
Virtual memory is a memory management technique used by operating systems to provide an illusion to the users that each process has its dedicated memory. It extends the available physical memory by using a combination of RAM (Random Access Memory) and disk space. In virtual memory systems, each process is given a contiguous block of virtual memory, which may exceed the actual physical memory available. The operating system then uses a mechanism called paging or segmentation to swap data between the physical memory and the disk, allowing processes to execute even if the entire program or data set cannot fit into the physical RAM.

Buffer:
A buffer is a temporary storage area in computer memory used to hold data while it's being transferred from one place to another. Buffers are employed to address differences in data transfer rates between two devices or processes. For example, in input/output operations, a buffer is often used to hold data temporarily as it's transferred between a slower peripheral (like a hard disk) and a faster component (such as RAM). Buffers help smooth out these differences and improve overall system performance by reducing the impact of speed mismatches between the producing and consuming elements in a computing system.

Use recursion method