Leetcode•Mar 18, 2025
581. Shortest Unsorted Continuous Subarray
Hazrat Ali
Leetcode
Given an integer array nums, you need to find one continuous subarray such that if you only sort this subarray in non-decreasing order, then the whole array will be sorted in non-decreasing 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
/**
* Shortest Unsorted Continuous Subarray
*
* 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:
*
* - Then length of the input array is in range [1, 10,000].
* - The input array may contain duplicates, so ascending order here means <=.
*/
Solution :
/**
* @param {number[]} nums
* @return {number}
*/
const findUnsortedSubarray = nums => {
let min = Infinity;
let max = -Infinity;
let flag = false;
for (let i = 1; i < nums.length; i++) {
if (nums[i] < nums[i - 1]) {
flag = true;
}
if (flag) {
min = Math.min(min, nums[i]);
}
}
flag = false;
for (let i = nums.length - 2; i >= 0; i--) {
if (nums[i] > nums[i + 1]) {
flag = true;
}
if (flag) {
max = Math.max(max, nums[i]);
}
}
let l, r;
for (l = 0; l < nums.length; l++) {
if (min < nums[l]) break;
}
for (r = nums.length - 1; r >= 0; r--) {
if (max > nums[r]) break;
}
return r - l < 0 ? 0 : r - l + 1;
};