# 414. Third Maximum Number

## Description

Given an integer array nums, return the third distinct maximum number in this array. If the third maximum does not exist, return the maximum number.

Example 1:

Input: nums = [3,2,1]
Output: 1
Explanation:
The first distinct maximum is 3.
The second distinct maximum is 2.
The third distinct maximum is 1.


Example 2:

Input: nums = [1,2]
Output: 2
Explanation:
The first distinct maximum is 2.
The second distinct maximum is 1.
The third distinct maximum does not exist, so the maximum (2) is returned instead.


Example 3:

Input: nums = [2,2,3,1]
Output: 1
Explanation:
The first distinct maximum is 3.
The second distinct maximum is 2 (both 2's are counted together since they have the same value).
The third distinct maximum is 1.


Constraints:

• 1 <= nums.length <= 104
• -231 <= nums[i] <= 231 - 1

Follow up: Can you find an O(n) solution?

## Solutions

• class Solution {
public int thirdMax(int[] nums) {
long m1 = Long.MIN_VALUE;
long m2 = Long.MIN_VALUE;
long m3 = Long.MIN_VALUE;
for (int num : nums) {
if (num == m1 || num == m2 || num == m3) {
continue;
}
if (num > m1) {
m3 = m2;
m2 = m1;
m1 = num;
} else if (num > m2) {
m3 = m2;
m2 = num;
} else if (num > m3) {
m3 = num;
}
}
return (int) (m3 != Long.MIN_VALUE ? m3 : m1);
}
}

• class Solution {
public:
int thirdMax(vector<int>& nums) {
long m1 = LONG_MIN, m2 = LONG_MIN, m3 = LONG_MIN;
for (int num : nums) {
if (num == m1 || num == m2 || num == m3) continue;
if (num > m1) {
m3 = m2;
m2 = m1;
m1 = num;
} else if (num > m2) {
m3 = m2;
m2 = num;
} else if (num > m3) {
m3 = num;
}
}
return (int) (m3 != LONG_MIN ? m3 : m1);
}
};

• class Solution:
def thirdMax(self, nums: List[int]) -> int:
m1 = m2 = m3 = -inf
for num in nums:
if num in [m1, m2, m3]:
continue
if num > m1:
m3, m2, m1 = m2, m1, num
elif num > m2:
m3, m2 = m2, num
elif num > m3:
m3 = num
return m3 if m3 != -inf else m1


• func thirdMax(nums []int) int {
m1, m2, m3 := math.MinInt64, math.MinInt64, math.MinInt64
for _, num := range nums {
if num == m1 || num == m2 || num == m3 {
continue
}
if num > m1 {
m3, m2, m1 = m2, m1, num
} else if num > m2 {
m3, m2 = m2, num
} else if num > m3 {
m3 = num
}
}
if m3 != math.MinInt64 {
return m3
}
return m1
}