class Solution {
  public boolean containsDuplicate(int[] nums) {
      Set<Integer> set = new HashSet<Integer>();
      for(int num : nums){
          if(!set.add(num)){
              return true;
          }
      }
      return false;
  }
}

The above solution is for the "Contains Duplicate" problem. It checks whether there are any duplicate elements in the given integer array nums. Here's how the code works:

1. The containsDuplicate function takes an integer array nums as input and returns a boolean value indicating whether the array contains any duplicate elements.
2. It initializes a Set named set to store encountered elements.
3. The loop iterates through the array using a for-each loop.
4. Inside the loop:
   • For each element num, the add method of the set is called. If the element is already present in the set (i.e., it's a duplicate), the add method will return false, and the function immediately returns true, indicating the presence of duplicates.
5. If the loop completes without finding any duplicates, the function returns false.

The code efficiently uses a Set data structure to keep track of encountered elements. If an element is already present in the set, it means a duplicate has been found. Otherwise, the element is added to the set for future comparison.

This code provides a simple and efficient solution to determine whether an array contains duplicate elements.