博客
关于我
LeetCode.581 Shortest Unsorted Continuous Subarray
阅读量:806 次
发布时间:2019-03-17

本文共 2372 字,大约阅读时间需要 7 分钟。

To solve this problem, we need to find the shortest continuous subarray such that sorting this subarray in ascending order would make the entire array sorted in ascending order as well.

Approach

The approach to solve this problem involves the following steps:

  • Sort the Array: First, we create a sorted version of the input array. This helps us identify the segments of the array that are out of order.

  • Identify Differences: We compare the original array with the sorted array to find the indices where they first differ (start of the unsorted segment) and where they last differ (end of the unsorted segment).

  • Determine the Subarray Length: The length of the shortest subarray that needs to be sorted is given by the range from the first differing index to the last differing index, inclusive.

  • Solution Code

    public class Solution {    public int findMinimumSubarrayLength(int[] nums) {        int n = nums.length;        int[] sorted = Arrays.copyOf(nums, n);        Arrays.sort(sorted);                int start = 0;        while (start < n && sorted[start] == nums[start]) {            start++;        }                if (start >= n) {            return 0;        }                int end = n - 1;        while (end >= 0 && sorted[end] == nums[end]) {            end--;        }                return end - start + 1;    }}

    Explanation

  • Sorting the Array: We create a sorted version of the input array to compare against the original array and identify the unsorted segments.

  • Finding the Start of the Subarray: By iterating through the original array, we find the first index where the value does not match the corresponding value in the sorted array. This index marks the beginning of the segment that needs to be sorted.

  • Finding the End of the Subarray: Similarly, by iterating from the end of the array, we find the last index where the value does not match the corresponding value in the sorted array. This index marks the end of the segment that needs to be sorted.

  • Calculating the Length: The length of the subarray is calculated as the difference between the end and start indices, plus one.

  • This approach ensures that we efficiently find the shortest subarray that, when sorted, will result in the entire array being sorted. The time complexity is dominated by the sorting step, making it (O(n \log n)), which is efficient for large arrays up to 10,000 elements.

    转载地址:http://ekjez.baihongyu.com/

    你可能感兴趣的文章
    poj 2236
    查看>>
    POJ 2243 Knight Moves
    查看>>
    POJ 2262 Goldbach's Conjecture
    查看>>
    POJ 2362 Square DFS
    查看>>
    poj 2386 Lake Counting(BFS解法)
    查看>>
    poj 2387 最短路模板题
    查看>>
    POJ 2391 多源多汇拆点最大流 +flody+二分答案
    查看>>
    POJ 2403
    查看>>
    poj 2406 还是KMP的简单应用
    查看>>
    POJ 2431 Expedition 优先队列
    查看>>
    Qt笔记——获取位置信息的相关函数
    查看>>
    POJ 2484 A Funny Game(神题!)
    查看>>
    POJ 2486 树形dp
    查看>>
    POJ 2488:A Knight&#39;s Journey
    查看>>
    SpringBoot为什么易学难精?
    查看>>
    poj 2545 Hamming Problem
    查看>>
    poj 2723
    查看>>
    poj 2763 Housewife Wind
    查看>>
    Qt笔记——模型/视图MVD 文件目录浏览器软件
    查看>>
    POJ 2892 Tunnel Warfare(树状数组+二分)
    查看>>