题目描述
Given an array, rotate the array to the right by k steps, where k is non-negative.
Example1:
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]
Example2:
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?
解题思路
- 一种是翻转前半段，翻转后半段，翻转全部，即可达到翻转字符串的目的
- 一种是 尾插法，然后erase初节点
class Solution {
public:
void rotate(vector<int>& nums, int k) {
/*int n = nums.size();
k %= nums.size();
for(int i = 0; i < n - k; i++){
nums.push_back(nums[0]);
nums.erase(nums.begin());
}*/
int n = nums.size();
k %= nums.size();
reverse(nums.begin(), nums.begin() + n - k);
reverse(nums.begin() + n - k, nums.end());
reverse(nums.begin(), nums.end());
}
};
