LeetCode Entry

3783. Mirror Distance of an Integer

18.04.2026 easy 2026 kotlin rust

Diff with reversal

3783. Mirror Distance of an Integer easy substack youtube

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Problem TLDR

Diff with reversal #easy

Intuition

Reverse and subtract. Can’t be done in-place, because we need to know the length of number.

Approach

• Kotlin’s shortest is strings reversal
• Rust doesn’t have divmod, but can use asm that will mutate ‘x’ and return reminder let d: i32; unsafe { asm!("cdq;div {0}", in(reg) 10, inout("eax") x, out("edx") d) }

Complexity

• Time complexity: \(O(lg(n))\)

• Space complexity: \(O(1)\)

Code

// 10ms
    fun mirrorDistance(n: Int) =
    abs(n - "$n".reversed().toInt())

// 0ms
    pub fn mirror_distance(n: i32) -> i32 {
        let (mut r, mut x) = (0, n);
        while x > 0 { r = r*10+x%10; x/=10}; (r-n).abs()
    }