Recover Rotated Sorted Array
26% Accepted
Given a rotated sorted array, recover it to sorted array in-place.
Have you met this question in a real interview? Yes
Example
[4, 5, 1, 2, 3] -> [1, 2, 3, 4, 5]
Challenge
- In-place, O(1) extra space and O(n) time.
Clarification
What is rotated array?
For example, the orginal array is [1,2,3,4], The rotated array of it can be [1,2,3,4], [2,3,4,1], [3,4,1,2], [4,1,2,3]
Tags Expand
Sorted Array
思路
- 左边翻转,右边翻转,整体翻转
public class Solution {
/**
* @param nums: The rotated sorted array
* @return: The recovered sorted array
*/
private void reverse(ArrayList<Integer> nums, int start, int end) {
for (int i = start, j = end; i < j; i++, j--) {
int temp = nums.get(i);
nums.set(i, nums.get(j));
nums.set(j, temp);
}
}
public void recoverRotatedSortedArray(ArrayList<Integer> nums) {
for (int index = 0; index < nums.size() - 1; index++) {
if (nums.get(index) > nums.get(index + 1)) {
reverse(nums, 0, index);
reverse(nums, index + 1, nums.size() - 1);
reverse(nums, 0, nums.size() - 1);
return;
}
}
}
}