Java O(n) 10 lines consice solution


  • 10
    S
    public class Solution {
        public void wiggleSort(int[] nums) {
            for (int i = 1; i < nums.length; i++)
                if ((i % 2 == 1 && nums[i] < nums[i - 1]) || (i % 2 == 0 && nums[i] > nums[i - 1])) {
                    int tmp = nums[i];
                    nums[i] = nums[i - 1];
                    nums[i - 1] = tmp;
                }
        }
    }

  • 0
    H

    Thanks for sharing. But does it work for the following case?

    int[] nums = {1,1,1,1,1,2,2,2,2,2};


  • 0
    N

    @happyLucia
    Hi!
    When I tried your case, the OJ just printed out "[1,1,1,1,1,2,2,2,2,2]".
    But my another solution may work.

    class Solution {
    public:
        void wiggleSort(vector<int>& nums) {
            if (nums.empty()) {
                return;
            }
            sort(nums.begin(), nums.end());
            swap(nums.back(), nums[nums.size() / 2]);
            if (nums.size() % 2) {
                wiggleSort(nums, 0, nums.size() - 2);
            } else {
                wiggleSort(nums, 0, nums.size() - 1);
            }
        }
    private:
        void wiggleSort(vector<int>& nums, int l, int r) {
            if (l < r - 1) {
                int _size = r - l + 1, i = l + _size / 4, mid = l + _size / 2, j = l + 3 * _size / 4;
                reverse(nums.begin() + i, nums.begin() + mid);
                reverse(nums.begin() + mid, nums.begin() + j);
                reverse(nums.begin() + i, nums.begin() + j);
                wiggleSort(nums, l, l + 2 * (i - l) - 1);
                wiggleSort(nums, l + 2 * (i - l), r);
            }
        }
    };
    

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