LeetCode in TypeScript

209. Minimum Size Subarray Sum

Medium

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.

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 <= 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)).

Solution

function minSubArrayLen(target: number, nums: number[]): number {
    let i = 0
    let j = 0
    let sum = 0
    let min = Number.MAX_SAFE_INTEGER
    while (j < nums.length) {
        sum += nums[j]
        if (sum >= target) {
            while (i <= j) {
                if (sum - nums[i] >= target) {
                    sum -= nums[i]
                    i++
                } else {
                    break
                }
            }
            min = Math.min(min, j - i + 1)
        }
        j++
    }
    return min === Number.MAX_SAFE_INTEGER ? 0 : min
}

export { minSubArrayLen }

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