Title
Rotate an array of n elements to the right by k steps.
For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].
Note: Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
[show hint]
Related problem: Reverse Words in a String II
题目大意，把数组循环右移k个
Solution
反转
//cpp:
class Solution {
public:
void rotate(vector<int>& nums, int k) {
int n = nums.size();
k = k % n;
reverse(nums.begin(), nums.begin() + n - k);
reverse(nums.end() - k, nums.end());
reverse(nums.begin(), nums.end());
}
};
也可以用额外的数组，as below
public class Solution {
public void rotate(int[] nums, int k) {
int[] a = new int[nums.length];
for (int i = 0; i < nums.length; i++) {
a[(i + k) % nums.length] = nums[i];
}
for (int i = 0; i < nums.length; i++) {
nums[i] = a[i];
}
}
}