Problem:
Given an array, rotate the array to the right by k steps, where k is non-negative.
Example 1:
Input: [1,2,3,4,5,6,7] and k = 3
Output: [5,6,7,1,2,3,4]
Explanation:
rotate 1 steps to the right: [7,1,2,3,4,5,6]
rotate 2 steps to the right: [6,7,1,2,3,4,5]
rotate 3 steps to the right: [5,6,7,1,2,3,4]
Example 2:
Input: [-1,-100,3,99] and k = 2
Output: [3,99,-1,-100]
Explanation:
rotate 1 steps to the right: [99,-1,-100,3]
rotate 2 steps to the right: [3,99,-1,-100]
Note:
- Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
- Could you do it in-place with O(1) extra space?
思路：
Solution (C++):
void rotate(vector<int>& nums, int k) {
int n = nums.size();
k %= n;
vector<int> tmp(k, 0);
for (int i = 0; i < k; ++i) {
tmp[i] = nums[i+n-k];
}
for (int i = n-1; i >= k; --i) {
nums[i] = nums[i-k];
}
for (int i = 0; i < k; ++i) {
nums[i] = tmp[i];
}
}
性能：
Runtime: 12 ms Memory Usage: 7.4 MB
思路：
Solution (C++):
性能：
Runtime: ms Memory Usage: MB
