[Swift]LeetCode581. 最短无序连续子数组 | Shortest Unsorted Continuous Subarray

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Given an integer array, you need to find one continuous subarray that if you only sort this subarray in ascending order, then the whole array will be sorted in ascending order, too.

You need to find the shortest such subarray and output its length.

Example 1:

Input: [2, 6, 4, 8, 10, 9, 15]
Output: 5
Explanation: You need to sort [6, 4, 8, 10, 9] in ascending order to make the whole array sorted in ascending order.

 Note:

1. Then length of the input array is in range [1, 10,000].
2. The input array may contain duplicates, so ascending order here means <=.

---

给定一个整数数组，你需要寻找一个连续的子数组，如果对这个子数组进行升序排序，那么整个数组都会变为升序排序。

你找到的子数组应是最短的，请输出它的长度。

示例 1:

输入: [2, 6, 4, 8, 10, 9, 15]
输出: 5
解释: 你只需要对 [6, 4, 8, 10, 9] 进行升序排序，那么整个表都会变为升序排序。

说明 :

1. 输入的数组长度范围在 [1, 10,000]。
2. 输入的数组可能包含重复元素 ，所以升序的意思是<=。

---

32ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
        let count = nums.count
        var (left,right)=(0,count-1)
        while left<count-1, nums[left]<=nums[left+1] {
            left += 1
        }
        while right>left, nums[right]>=nums[right-1]{
            right -= 1
        }
        if left == right {
            return 0
        }
        var (mini,maxi) = (nums[left],nums[right])
        for i in left...right {
            mini = min(mini, nums[i])
            maxi = max(maxi, nums[i])
        }
        while left>=0,nums[left]>mini {
            left -= 1
        }
        while right<count,nums[right]<maxi {
            right += 1
        }
        return right-left-1
    }
}

---

36ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
        let n = nums.count
        var start = -1
        var end = -2
        var minNum = nums[n - 1]
        var maxNum = nums[0]
        
        for i in 1..<n {
            maxNum = max(maxNum, nums[i])
            minNum = min(minNum, nums[n - 1 - i])
            if nums[i] < maxNum {
                end = i
            }
            if nums[n - 1 - i] > minNum {
                start = n - 1 - i
            }
        }
        
        return end - start + 1 
    }
}

---

48ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
        let length = nums.count
        var minNum = nums[length - 1]
        var maxNum = nums[0]
        var begin = -1
        var end = -2
        var i = 0
        
        while i < length {
            maxNum = max(maxNum, nums[i])
            minNum = min(minNum, nums[length-i-1])
            
            if nums[i] < maxNum {
                end = i
            }
            if nums[length-i-1] > minNum {
                begin = length-i-1
            }
            i += 1
        }
           
        return end - begin + 1
    }
}

---

60ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
                if nums.count == 0 {
            return 0
        }
        
        var rightIndex : Int = 0
        var max : Int = nums[0]
        for index in 1 ..< nums.count {
            if nums[index] >= max {
                max = nums[index]
            } else {
                rightIndex = index
            }
        }
        
        var leftIndex : Int = 0
        var min : Int = nums[nums.count - 1]
        for index in (0 ..< nums.count - 1).reversed() {
            if nums[index] <= min {
                min = nums[index]
            } else {
                leftIndex = index
            }
        }
        
        return rightIndex != leftIndex ? rightIndex - leftIndex + 1 : 0
    }
}

208ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
        var sorted = nums.sorted()
        var start = nums.count
        var end = 0
        for index in nums.indices {
            if sorted[index] != nums[index] {
                start = min(start, index)
                end = max(end, index)
            }
        } 
        return end - start >= 0 ? end - start + 1 : 0
    }
}

---

320ms

class Solution {
    func findUnsortedSubarray(_ nums: [Int]) -> Int {
        var arr:[Int] = nums
        //升序排序
        arr.sort(){$0 < $1}
        var i:Int = 0 , j:Int = nums.count - 1
        while(nums[i] == arr[i] && i < j)
        {
            i += 1
        }        
        while(nums[j] == arr[j] && i < j)
        {
            j -= 1
        }
        if i == j
        {
            return 0
        }
        else
        {
            return j - i + 1
        } 
    }
}