How does Java find the subarray with K
This article mainly explains "how to find a subarray of Java and K". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "how to find a subarray of K by Java".
Preorder sum
The definition sumi represents the sum added to the position I from the beginning, which we have on the array [1, 2, 3, 4].
Sum [0] = nums [0]
Sum [1] = nums [0] + nums [1] = sum [0] + nums [1]
Sum [2] = nums [0] + nums [1] + nums [2] = sum [0] + nums [1] + nums [2] = sum [1] + nums [2]
Sum [3] = nums [0] + nums [1] + nums [2] + nums [3] = sum [0] + nums [1] + nums [2] + nums [3] =.
We found that we have done a lot of repeated calculations, and these are the places where we can optimize and deform the third formula above.
Sum [1]-sum [0] = nums [1]
Sum [2]-sum [0] = nums [1] + nums [2]
Sum [2]-sum [1] = nums [2]
Sum [I]-sum [j] is the sum of consecutive arrays between sum [I]-sum [j] = k, then we can count, here we can also do a transformation sum [j] = sum [I]-k, we use a hash table to record sum [j], and we count when it occurs again.
Func subarraySum (nums [] int, k int) int {res,sum,m: = 0Pol 0, map [int] int {0:1} for iRu return res} i0 {res + = m [sum-k]} m [sum] +} return res} so far, I believe you have a deeper understanding of "how to find a subarray of Java and a subarray of K", you might as well do it in practice! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!
