16.LeetCode刷题For Swift·209. Mini
2021-01-06 本文已影响0人
富城
1、原题
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).
2、思路
3、代码
class Solution {
func minSubArrayLen(_ s: Int, _ nums: [Int]) -> Int {
// 结果,初始化为一个超大值,不能为空
var result = INTPTR_MAX
// 左指针
var i = 0
// 求和
var sum = 0
// 最小长度
var subLength = 0
for j in 0..<nums.count {
// 求和,判断和是否大于等于s
sum += nums[j]
while sum >= s {
// 小数组的长度
subLength = j - i + 1
result = result < subLength ? result : subLength
// 然后还得减去小数组的第一个元素
sum -= nums[i]
i += 1
}
}
return result == INTPTR_MAX ? 0 : result
}
}