LeetCode:Rotate Array

Problem:

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.

Solution:问题意思是要将末尾的数字依次右移 总共移动三次 则是左移n-k%n 采用三步反转。

 1 class Solution {
 2 public:
 3     void rotate(vector<int>& nums, int k) {
 4         int n=nums.size();
 5         int m=n-k%n;
 6         reverse(nums,0,m-1);
 7         reverse(nums,m,n-1);
 8         reverse(nums,0,n-1);
 9         
10     }
11     void reverse(vector<int>& nums,int from,int to)
12     {
13         while(from<to)
14         {
15             int temp=nums[from];
16             nums[from++]=nums[to];
17             nums[to--]=temp;
18         }
19     }
20 };

 

posted @ 2015-07-02 10:00  尾巴草  阅读(112)  评论(0编辑  收藏  举报