LeetCode189 Rotate Array
问题描述
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.Related problem: Reverse Words in a String II
问题分析
这道题就是对数组以某个节点进行反转,有一种思路是先反转数组,然后在分别反转某节点的前后两部分数组。
代码实现
public void rotate(int[] nums, int k) {
if(nums==null||nums.length<1||k==0||k>=nums.length) return;
k %= nums.length;//k值超过数组长度时
reverse(nums, 0, nums.length-1);//翻转整个数组
reverse(nums, 0, k-1);//翻转前k个数
reverse(nums, k, nums.length-1);//翻转剩下的数
}
void reverse(int[] nums,int i,int j){
while (i < j) {
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
i++;
j--;
}
}
参考https://www.cnblogs.com/grandyang/p/4298711.html
大神的帖子里面介绍了更多的方法,大家可以去看一下。这里我就不重复的复制粘贴了。
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