1.描述
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.
2.分析
方法一：直接計算下標玷室，index = (i + k) % n寓辱，實現(xiàn)空間復雜度O(1)需要技巧。
方法二：翻轉(zhuǎn)數(shù)組的前n-k個數(shù)甫窟，再翻轉(zhuǎn)數(shù)組的后k個數(shù)，最后整個數(shù)組翻轉(zhuǎn)种冬。
方法三：翻轉(zhuǎn)整個數(shù)組镣丑，再翻轉(zhuǎn)前k個數(shù)，最后翻轉(zhuǎn)數(shù)組后n-k個數(shù)娱两。
3.代碼
class Solution {
public:
void rotate(vector<int>& nums, int k) {
if (nums.empty() || (k %= nums.size()) == 0) return;
int n = nums.size();
reverse(nums.begin(), nums.begin() + n - k);
reverse(nums.begin() + n - k, nums.end());
reverse(nums.begin(), nums.end());
}
};
