LeetCode Entry

2943. Maximize Area of Square Hole in Grid

15.01.2026 medium 2026 kotlin rust

Max square area after removing bars in a grid

2943. Maximize Area of Square Hole in Grid medium blog post substack youtube

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Problem TLDR

Max square area after removing bars in a grid #medium #intervals

Intuition

Count consequtive intervals separately for horizontal and vertical bars. Then min(max(h,v))^2.

One way: sort bars, count consequtive with counter Second way: use a HashMap(x, length) and update x-l, x+r with 1+m[x-1]+m[x+1]

Approach

• do +1 or just init counter with 2
• for the HashMap we can skip writing to the middle m[x]

Complexity

• Time complexity: \(O(nlog(n))\), or O(n)

• Space complexity: \(O(1)\) or O(n)

Code

// 22ms
    fun maximizeSquareHoleArea(n: Int, m: Int, h: IntArray, v: IntArray) =
        listOf(h,v).minOf { val m = HashMap<Int, Int>()
            1 + it.maxOf { x -> val l = m[x-1]?:0; val r = m[x+1]?:0
                (l+r+1).also{m[x-l]=it;m[x+r]=it}}
        }.let{it*it}

// 0ms
    pub fn maximize_square_hole_area(_: i32, _: i32, h: Vec<i32>, v: Vec<i32>) -> i32 {
        [h, v].map(|s| s.into_iter().sorted().collect::<Vec<_>>()
            .chunk_by(|a, b| b - a < 2).map(|c| c.len() + 1).max().unwrap_or(2)
        ).into_iter().min().unwrap().pow(2) as _
    }