LeetCode 189. Rotate Array
2017-10-23 本文已影响24人
关玮琳linSir
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.
[show hint]
Hint:
Could you do it in-place with O(1) extra space?
Related problem: Reverse Words in a String II
Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.
题意:翻转数组,k是要翻转多少遍。
java代码:
class Solution {
public void rotate(int[] nums, int k) {
k %= nums.length;
reverse(nums, 0, nums.length - 1);
reverse(nums, 0, k - 1);
reverse(nums, k, nums.length - 1);
}
private void reverse(int[] nums, int m, int n) {
while (m < n) {
int temp = nums[m];
nums[m++] = nums[n];
nums[n--] = temp;
}
}
}