go 代码
func rotate(nums []int, k int) {
len := len(nums)
k %= len
reverse(nums)
reverse(nums[:k])
reverse(nums[k:])
}
func reverse(nums []int) {
for l, r := 0, len(nums) - 1;l < r; {
nums[l],nums[r] = nums[r], nums[l]
l++
r--
}
}