[LeetCode] 209. Minimum Size Subarray Sum

轉自LeetCode

Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn't one, return 0 instead.

Example: 

Input: s = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: the subarray [4,3] has the minimal length under the problem constraint.

Follow up:

If you have figured out the O(n) solution, try coding another solution of which the time complexity is O(n log n). 

<Solution>

想法如下

• 用一個變數計算目前的 sum，當 sum >= s 的時候，開始找答案

• 當 sum >= s 這個條件成立時，計算出目前的 subarray 長度，然後縮起始位置並減掉該位置的值，看看 sum >= s 這個條件是不是還是成立，是的話，再重複做之前的動作

code 如下

Java(參考解法)

kotlin