414. Third Maximum Number

Problem Statement

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?

Solution:

Rust

impl Solution {
    pub fn third_max(nums: Vec<i32>) -> i32 {
        let mut sorted = nums.clone();
        // sort in descending order
        sorted.sort_by(|a, b| b.cmp(a));
        // remove duplicates
        sorted.dedup();

        if sorted.len() < 3 {
            return sorted[0];
        } else {
            return sorted[2];
        }
    }
}

414. Third Maximum Number #

Problem Statement #

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414. Third Maximum Number

Problem Statement

Solution:

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