414. Third Maximum Number

Given a non-empty array of integers, return the third maximum number in this array. If it does not exist, return the maximum number. The time complexity must be in O(n).

Example 1: Input: [3, 2, 1] Output: 1 Explanation: The third maximum is 1.

Example 2: Input: [1, 2] Output: 2 Explanation: The third maximum does not exist, so the maximum (2) is returned instead.

Example 3: Input: [2, 2, 3, 1] Output: 1 Explanation: Note that the third maximum here means the third maximum distinct number. Both numbers with value 2 are both considered as second maximum.

public int thirdMax(int[] nums) {
        Arrays.sort(nums);
        int count=0,value=nums[0];

        if (nums.length<3) {

            for (int i = 0; i < nums.length; i++)
                value=Math.max(value, nums[i]);

        }else {

            for (int i = nums.length-1; i > 0; i--) {
                if (nums[i]>nums[i-1]) {
                    count++;
                    if (count==2) {
                        value=nums[i-1];
                        break;
                    }
                }
            }
            if(count<2)
                value=nums[nums.length-1];
        }

        return value;
    }