18-Rotate Array-Leetcode
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
思路一:定位具体位置,保存至另一容器,时间O(n),空间O(n)
class Solution {
public:
void rotate(vector<int>& nums, int k) {
int n=nums.size();
if(k>n)k=k%n;
vector<int> tmp;
for(int i=n-k;i<n;++i)
{
tmp.push_back(nums[i]);
}
for(int i=0;i<n-k;++i)
{
tmp.push_back(nums[i]);
}
nums = tmp;
}
};
思路二:全部逆转,再分别逆转两部分,O(n),空间O(1)