题目:
题解:
class Solution {public List<Integer> findDuplicates(int[] nums) {int n = nums.length;List<Integer> ans = new ArrayList<Integer>();for (int i = 0; i < n; ++i) {int x = Math.abs(nums[i]);if (nums[x - 1] > 0) {nums[x - 1] = -nums[x - 1];} else {ans.add(x);}}return ans;}
}