circular-buffer

I have an array like [A,B,C,D] . I want to access that array within a for loop like as var arr = [A,B,C,D]; var len = arr.len; for(var i = 0;i<arr.len;i++){ 0 - A,B,C 1 - B,C,D 2 - C,D,A 3 - D,A,B } I want to access that like in JavaScript, any ideas? Try this: var arr = ["A","B","C","D"]; for (var i=0, len=arr.length; i<len; i++) { alert(arr.slice(0, 3).join(",")); arr.push(arr.shift()); } Without mutating the array, it would be for (var i=0, len=arr.length; i<len; i++) { var str = arr[i]; for (var j=1; j<3; j++) str += ","+arr[(i+j)%len]; // you could push to an array as well alert(str); } /

Consider a few web server instances running in parallel. Each server holds a reference to a single shared "Status keeper", whose role is keeping the last N requests from all servers. For example ( N=3 ): Server a: "Request id = ABCD" Status keeper=["ABCD"] Server b: "Request id = XYZZ" Status keeper=["ABCD", "XYZZ"] Server c: "Request id = 1234" Status keeper=["ABCD", "XYZZ", "1234"] Server b: "Request id = FOO" Status keeper=["XYZZ", "1234", "FOO"] Server a: "Request id = BAR" Status keeper=["1234", "FOO", "BAR"] At any point in time, the "Status keeper" might be called from a monitoring

We want to search for a given element in a circular sorted array in complexity not greater than O(log n) . Example: Search for 13 in {5,9,13,1,3} . My idea was to convert the circular array into a regular sorted array then do a binary search on the resulting array, but my problem was the algorithm I came up was stupid that it takes O(n) in the worst case: for(i = 1; i < a.length; i++){ if (a[i] < a[i-1]){ minIndex = i; break; } } then the corresponding index of ith element will be determined from the following relation: (i + minInex - 1) % a.length it is clear that my conversion (from circular

Has anyone already implemented a circular buffer in JavaScript? How would you do that without having pointers? bobince Strange co-incidence, I just wrote one earlier today! I don't know what exactly your requirements are but this might be of use. It presents an interface like an Array of unlimited length, but ‘forgets’ old items: // Circular buffer storage. Externally-apparent 'length' increases indefinitely // while any items with indexes below length-n will be forgotten (undefined // will be returned if you try to get them, trying to set is an exception). // n represents the initial length

I have data that is arranged in a ring structure (or circular buffer ), that is it can be expressed as sequences that cycle: ...-1-2-3-4-5-1-2-3-.... See this picture to get an idea of a 5-part ring: I'd like to create a window query that can combine the lag and lead items into a three point array, but I can't figure it out. For example at part 1 of a 5-part ring, the lag/lead sequence is 5-1-2, or at part 4 is 3-4-5. Here is an example table of two rings with different numbers of parts (always more than three per ring): create table rp (ring int, part int); insert into rp(ring, part) values(1