Can you explain what the operational complexity O(1) means for an algorithm?

Constant time complexity O(1) means that the execution time of an algorithm or operation does not depend on the size of the input data — it remains constant.

For example, accessing an array element by index is an O(1) operation because, regardless of the array size, the element can be retrieved in the same amount of time.

Example in Java:

int[] arr = {10, 20, 30, 40};
int element = arr[2]; // access to element with index 2 — O(1)