0209 - Minimum Size Subarray Sum

0209 - Minimum Size Subarray Sum

Given an array of positive integers nums and a positive integer target, return the minimal length of a contiguous subarray [numsl, numsl+1, ..., numsr-1, numsr] of which the sum is greater than or equal to target. If there is no such subarray, return 0 instead.

Examples

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.

Input: target = 4, nums = [1,4,4] Output: 1

Input: target = 11, nums = [1,1,1,1,1,1,1,1] Output: 0

Constraints:

• 1 <= target <= 109

• 1 <= nums.length <= 105

• 1 <= nums[i] <= 105

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))

Java Solution

class Solution {
    public int minSubArrayLen(int target, int[] nums) {
        int result = Integer.MAX_VALUE;
        int left = 0;
        int sum = 0;
        
        for(int i = 0; i < nums.length; i++) {
            sum += nums[i];
            while(sum >= target) {
                result = Math.min(result, i - left + 1);
                sum -= nums[left++];
            }
        }
        return result == Integer.MAX_VALUE ? 0 : result;
    }
}