On 6/23/15 1:51 AM, jkpl wrote:
On Tuesday, 23 June 2015 at 05:16:23 UTC, Assembly wrote:
What's a fast way to insert an element at index 0 of array? now that
the code is working I want to clean this:
void push(T val)
{
T[] t = new T[buffer.length + 1];
t[0] = val;
t[1 .. $] = buffer;
buffer = t;
}
I did this because I didn't find any suble built-in data structure
that let me insert an item into a specific index at first search.
Slist does have insertFron(), exactly what I'm looking for it's a
linked list.
* Option 1/
if most of the time you have to insert at the beginning, then start
reading from the end and append to the end, so that the existing block
has not to be moved. You just have to add val at the end.
* Option 2/
better way to move the whole block (this can be done with memmove too).
---
void push(T val)
{
buffer.length += 1;
buffer[1..$] = buffer[0..$-1];
This will fail.
http://dlang.org/arrays.html#overlapping-copying
I will note, dcollections had a deque, which allowed insertion at the
front in O(1) (amortized) time. It basically worked by having 2 arrays
front to front.
-Steve
