Question

I have a particular array, by which I wanted to check if two values within the array equal the value passed into the function, and if the two integers do, then pass it into a new array.

I have solved this by using two backwards while loops and caching the length as a variable, which seemed to be efficient. However, someone mentioned to me there might be a way to remove the need for one of the loops and making it much more efficient and thus optimizing the BIG O notation.

Any ideas how this could be done? This is what I have…

var intArray = [1, 3, 7, 8, 10, 4, 6, 13, 0],
    newArray = [],
    i = intArray.length;


function arrayCheck(k) {
    while(i--) {
        var z = i;
        while (z--) {
            if (intArray[i] + intArray[z] === k) {
                newArray.push(intArray[i]);
                newArray.push(intArray[z]);
            }
        }
    }
    alert(newArray);
}

arrayCheck(8);

Answer 1

There is an algorithm that solves this problem in linear [O(n)] time. I recommend you check out this SO answer.

Also, as others have stated, marking answers as accepted will make people more likely to answer your questions. You may wish to revisit questions you’ve previously asked and accept any answers that deserve it.