1. class Solution {
    2.     public boolean containsDuplicate(int[] nums) {
    3.         HashMap map = new HashMap(16);
    4.         for (int i = 0; i < nums.length; i++) {
    5.             if (map.containsKey(nums[i])) {
    6.                 return true;
    7.             }
    8.             map.put(nums[i], 1);
    9.         }
    10.         return false;
    11.     }
    12. }