lintcode Recover Rotated Sorted Array

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]

zh找到轴点，分别交换三次

class Solution {
public:
void recoverRotatedSortedArray(vector<int> &nums) {
// write your code here
int len = nums.size();
if (0 == len) {
return ;
}
int t = 0;
for (int i = 0; i < len; ++i) {
if (nums[i] < nums[t] ) {
t = i;
}
}
reverse(nums,0,t-1);
reverse(nums,t,len-1);
reverse(nums,0,len-1);
}
void reverse(vector<int> &nums,int lo,int hi) {
while (lo<hi) {
swap(nums[lo],nums[hi]);
++lo;
--hi;
}
}
};