What is the sliding window technique?
The sliding window technique is a common algorithmic approach used to create a fixed-sized window that moves through the data one step at a time, typically from left to right, to perform specific operations or computations on the elements within the window.
What is the sliding window algorithm?
The sliding window algorithm is a method for finding a subset of elements that satisfy certain conditions in a given problem.
How does the sliding window algorithm work?
Let’s look at the “maximum sum of a subarray” problem to better understand how it works:
Problem: Given an array of integers, find the maximum sum of a subarray with a fixed window size.
In this case, the sliding window algorithm uses a fixed size window that the user can pass to a function as a parameter. It iterates through all the elements inside that window by accessing the current value(nums[i]) and previous value(nums[i - k]) and calculates the window sum, which is needed to determine the max sum result.
Code Example
func maxSubArraySum(_ nums: [Int], _ k: Int) -> Int {
var maxSum = Int.min
var windowSum = nums[0 ..< k].reduce(0, +)
for i in k ..< nums.count {
windowSum += nums[i] - nums[i - k]
maxSum = max(maxSum, windowSum)
}
return maxSum
}