LeetCode Entry

744. Find Smallest Letter Greater Than Target

31.01.2026 easy 2026 kotlin rust

Larger letter in array

744. Find Smallest Letter Greater Than Target easy blog post substack youtube

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Problem TLDR

Larger letter in array #easy

Intuition

Scan. Or do a binary search.

Approach

• or search in t+1..’z’

Complexity

• Time complexity: \(O(n)\)

• Space complexity: \(O(1)\)

Code

// 1ms
    fun nextGreatestLetter(l: CharArray, t: Char) =
    l.find{it>t}?:l[0]
    /*
    (l.filter{it>t}+l[0])[0]
    l[l.count{it<=t}%l.size]
    (l.map{it}-('a'..t)+l[0])[0]
    (t+1..'z').find{it in l}?:l[0]
    l[(-1-l.map{it}.binarySearch{if(it>t)1 else -1})%l.size]
    l[(Arrays.binarySearch(l,t+1).let{if(it<0)-1-it else it})%l.size]
    */

// 0ms
    pub fn next_greatest_letter(l: Vec<char>, t: char) -> char {
        l[l.partition_point(|&c|c<=t)%l.len()]
    }