209. Subarray with the smallest length

subject ：

Answer key ：
For this question , There is a word in the question that requires Continuous subarray , For this requirement continuous , Sliding windows should be considered first . Then the question is to find the shortest continuous sub array, so when traversing this array , The general idea is as follows ：

• Combination of values in the window < target : The length of the window +1
• Combination of values in the window >= target : Compare the current window length with the shortest length recorded , And the window length -1

For window length +1 operation , Is to expand an element on the right side of the window , For window length -1 The operation of , Is to subtract an element from the left

Here are Go The language code ：

func minSubArrayLen(target int, nums []int) int {
    
	min := len(nums) + 1
	winLen := 1
	sum := nums[0]
	for i := 0; ; {
    
		if sum < target {
    
			if i+winLen == len(nums) {
    
				break
			}
			winLen++
			sum = sum + nums[i+winLen-1]
		}
		if sum >= target {
    
			if winLen < min {
    
				min = winLen
			}
			sum = sum - nums[i]
			i++
			winLen--
		}
	}
	if min == len(nums)+1 {
    
		return 0
	} else {
    
		return min
	}
}