Array

Runtime Complexity

Lookup (by index) - O(1)
Lookup (by value) - O(n)
Insert - O(n)
Delete - O(n)

In cases when lots of inserts/removals are needed, a Linked List is a better option (unless we add/remove in the middle).

Binary Search

var search = function(nums, target) {
    let minIndex = 0;
    let maxIndex = nums.length - 1;

    while (minIndex <= maxIndex) {
        let halfIndex = minIndex + Math.floor((maxIndex - minIndex) / 2);

        if (nums[halfIndex] === target) {
            return halfIndex;
        }
        else if (nums[halfIndex] < target) {
            minIndex = halfIndex + 1;
        }
        else {
            maxIndex = halfIndex - 1;
        }
    }

    return -1;
};

← Big O Notation

Linked List →