class Solution { public void rotate(int[] nums, int k) { /* 1234567 k 3 反转 7654321 反转前k个元素[0-(k-1)] : 5,6,7,4,3,2,1; 反转[k-n-1]:5,6,7,1,2,3,4; */ k%nums.length; reverse(nums,0,nums.length-1); reverse(nums,0,k-1); reverse(nums,k,nums.length-1); } public void reverse(int[]nums,int l,int r){ while(lr){ int temp nums[l]; nums[l] nums[r]; nums[r] temp; l;r--; } } }