LeetCode Entry

628. Maximum Product of Three Numbers

26.07.2026 easy 2026 kotlin rust

Max product of 3 numbers

628. Maximum Product of Three Numbers easy substack youtube

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Problem TLDR

Max product of 3 numbers

Intuition

Take 3 largest and compare with taking two smallest and a one largest.

Approach

• Rust itertools has k_largest, s_smallest (the results are sorted differently)

Complexity

• Time complexity: \(O(n)\)

• Space complexity: \(O(1)\)

Code

    fun maximumProduct(n: IntArray) = run { n.sort()
    val l = n.size-1; max(n[0]*n[1]*n[l], n[l]*n[l-1]*n[l-2])}

    pub fn maximum_product(n: Vec<i32>) -> i32 {
        let (a,b) = n.iter().copied().k_smallest(2).collect_tuple().unwrap();
        let (z,y,x) = n.iter().copied().k_largest(3).collect_tuple().unwrap();
        (a*b*z).max(x*y*z)
    }