Last Updated on 2022-06-14 by Clay
題目
Given an integer array nums, 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.
Return the shortest such subarray and output its length.
Example 1:
Input: nums = [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.
Example 2:
Input: nums = [1,2,3,4] Output: 0
Example 3:
Input: nums = [1] Output: 0
Constraints:
1 <= nums.length <= 104-105 <= nums[i] <= 105
Follow up: Can you solve it in O(n) time complexity?
解題紀錄
優化解法
優化解法複雜度
| Time complexity | O(n) |
| Space complexity | O(1) |
優化解法 C++ 範例程式碼
class Solution {
public:
int findUnsortedSubarray(vector<int>& nums) {
int start = -1;
int end = -1;
int _max = INT_MIN;
for (int i=0; i<nums.size(); ++i) {
if (_max > nums[i]) {
if (start == -1) start = i-1;
while (start-1 >= 0 && nums[start-1] > nums[i]) {
--start;
}
end = i+1;
}
else _max = nums[i];
}
return end - start;
}
};