Problem
Given an array of positive integers nums and a positive integer target, return **the *minimal length* of a subarray whose sum is greater than or equal to** target. If there is no such subarray, return 0 instead.
Example 1:
Input: target = 7, nums = [2,3,1,2,4,3] Output: 2 Explanation: The subarray [4,3] has the minimal length under the problem constraint. Example 2:
Input: target = 4, nums = [1,4,4] Output: 1 Example 3:
Input: target = 11, nums = [1,1,1,1,1,1,1,1] Output: 0 Constraints:
1 <= target <= 1091 <= nums.length <= 1051 <= nums[i] <= 104
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
/** * @param {number} target * @param {number[]} nums * @return {number} */ var minSubArrayLen = function(target, nums) { var left = 0; var right = 0; var sum = nums[0]; var min = Number.MAX_SAFE_INTEGER; while (right < nums.length && left <= right) { if (sum < target) { right++; sum += nums[right]; } else { min = Math.min(min, right - left + 1); sum -= nums[left]; left++; } } return min === Number.MAX_SAFE_INTEGER ? 0 : min; }; Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(1).