Why are two arrays (temp and result) needed?

Using two arrays — temp and result — is common in algorithms where intermediate data storage is required for correct processing or optimization.

For example, in merge sort, one array is used to store the original data, and the other for temporary storage of merge results. This helps avoid conflicts during simultaneous reading and writing.

Another example is when calculating new values based on old ones (e.g., dynamic programming or state updates), where temp can store intermediate calculations, and result holds the final values after an iteration.

This approach helps to:

• Avoid overwriting data that is still needed for calculations.
• Improve code readability and structure.
• Ensure algorithm correctness during parallel processing.

Example (Java):

int[] temp = new int[n];
int[] result = new int[n];

// Copy data into temp
System.arraycopy(result, 0, temp, 0, n);

// Update result based on temp
for (int i = 0; i < n; i++) {
    result[i] = temp[i] * 2; // example operation
}

Thus, two arrays help separate processing stages and prevent errors when modifying data.