Java | Leetcode Java题解之第324题摆动排序II
题目：
题解：
class Solution {Random random = new Random();public void wiggleSort(int[] nums) {int n = nums.length;int x = (n + 1) / 2;int mid = x - 1;int target = findKthLargest(nums, n - mid);for (int k = 0, i = 0, j = n - 1; k <= j; k++) {if (nums[transAddress(k, n)] > target) {while (j > k && nums[transAddress(j, n)] > target) {j--;}swap(nums, transAddress(k, n), transAddress(j--, n));}if (nums[transAddress(k, n)] < target) {swap(nums, transAddress(k, n), transAddress(i++, n));}}}public int findKthLargest(int[] nums, int k) {int left = 0, right = nums.length - 1;while (left <= right) {int pivot = random.nextInt(right - left + 1) + left;int newPivot = partitionAroundPivot(left, right, pivot, nums);if (newPivot == k - 1) {return nums[newPivot];} else if (newPivot > k - 1) {right = newPivot - 1;} else { left = newPivot + 1;}}return nums[k - 1];}public int transAddress(int i, int n) {return (2 * n - 2 * i - 1) % (n | 1);}public int partitionAroundPivot(int left, int right, int pivot, int[] nums) {int pivotValue = nums[pivot];int newPivot = left;swap(nums, pivot, right);for (int i = left; i < right; ++i) {if (nums[i] > pivotValue) {swap(nums, i, newPivot++);}}swap(nums, right, newPivot);return newPivot;}public void swap(int[] a, int i, int j) {int temp = a[i];a[i] = a[j];a[j] = temp;}
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