package array; import java.util.HashSet; import java.util.Set; /** * @ProjectName: leetcode * @Package: array * @ClassName: Array287 * @Author: markey * @Description: * @Date: 2020/5/26 21:40 * @Version: 1.0 */ public class Array287 { public int findDuplicate(int[] nums) { Set set = new HashSet<>(); for (int i = 0; i < nums.length; i++) { if (set.contains(nums[i])) { return nums[i]; } else { set.add(nums[i]); } } return 0; } }