D02-Array--leetcode - 217. Contains Duplicate

#217. Contains Duplicate
Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

Example 1:
Input: nums = [1,2,3,1]
Output: true

Example 2:
Input: nums = [1,2,3,4]
Output: false

Example 3:
Input: nums = [1,1,1,3,3,4,3,2,4,2]
Output: true

solution 1:

(1) sorting the array in ascending order
(2) traverse the list and compare the i th and i + 1 th number, if they are the same, return true. if they are all different, return false.

	Class Solution{
		public boolean ContainsDuplicate(int[] nums){
			//sorting the array with an ascending order
			Arrays.sort(nums);
			// traverse the array, and compare i and i + 1 elements
			for(int i = 0; i < nums.length - 1; i++){
				if(nums[i] == nums[i + 1]){
					return true;
				}
			}
			return false;
		}

}

(1) traverse all the elements in the array
(2) define a array container numbers to put distinct elements, if the numbers includes the element, return true. if the numbers does not include the element, put the element into the array container.

var ContainsDuplicate()= function(nums){
	let numbers = [];
	//traverse every elements in the nums
	for(let i of nums){
		if(!numbers.includes(i)){
			numbers.push(i);
		}else{
			return false;
		}
	}
	return true;
}