Techniques
PrefixSum
Technique for storing a cumulative sum of elements.
The PrefixSum technique consists of creating a final array with the previous sum of elements in each position of the array. It is similar to representing the snowball effect using an algorithm.
prefixSum[i] = arr[0] + arr[1] + … + arr[i]The power of PrefixSum lies
on efficient cumulative calculation.
Optimise repetitive operations.
DRY principle.
It may be used not only
on leetcode problems,
but also for real-life
operations.
As the Ubermensch follows,
the PrefixSum represents
the continuous life process
for self-overcoming.
Is today stronger than the past, taken as a whole?
Example code
class PrefixSumExample
{
public static int[] ComputePrefixSum(int[] arr)
{
int n = arr.Length;
int[] prefixSum = new int[n];
prefixSum[0] = arr[0];
for (int i = 1; i < n; i++)
{
prefixSum[i] = prefixSum[i - 1] + arr[i];
}
return prefixSum;
}
static void Main()
{
int[] arr = { 2, 4, 6, 8 };
int[] prefixSum = ComputePrefixSum(arr);
Console.WriteLine("Prefix Sum Array:");
foreach (var sum in prefixSum)
{
Console.Write(sum + " "); // Output: 2 6 12 20
}
}
}Source: Prefix Sums Demystified