Third maximum number

Array Sorting

38.9% acceptance

Jan 13, 2026

3509

3507

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.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn third_max(nums: Vec<i32>) -> i32 {
    let mut first = None;
    let mut second = None;
    let mut third = None;
    
    for &num in &nums {
      if first == Some(num) || second == Some(num) || third == Some(num) {
        continue;
      }
      
      if first.is_none() || num > first.unwrap() {
        third = second;
        second = first;
        first = Some(num);
      } else if second.is_none() || num > second.unwrap() {
        third = second;
        second = Some(num);
      } else if third.is_none() || num > third.unwrap() {
        third = Some(num);
      }
    }
    
    third.unwrap_or(first.unwrap())
  }
}