LeetCode Entry

2264. Largest 3-Same-Digit Number in String

14.08.2025 easy 2025 kotlin rust

Max 3-digit in string

2264. Largest 3-Same-Digit Number in String easy blog post substack youtube 1.webp

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Problem TLDR

Max 3-digit in string #easy

Intuition

Sliding window is accepted and the optimal

Approach

  • compare just a single char
  • let’s explore the variations: what if we check each digit individually?

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(1)\)

Code


// 26ms
    fun largestGoodInteger(num: String) = num.windowed(3)
    .filter { it.toSet().size < 2 }.maxByOrNull { it[0] } ?: ""



// 15ms
    fun largestGoodInteger(n: String) = (9 downTo 0)
        .map { "$it$it$it" }.find { it in n } ?: ""



// 0ms
    pub fn largest_good_integer(num: String) -> String {
        num.as_bytes().windows(3).filter(|w| w[0] == w[1] && w[1] == w[2])
        .max_by_key(|w| w[0]).map_or("".into(), |w| from_utf8(w).unwrap().into())
    }



// 0ms
    string largestGoodInteger(string n) {
        int c = 0, p = 0; char m = 0;
        for (auto x: n) c = p == x ? ++c : 1, p = x, m = c > 2 ? max(m, x):m;
        return m > 0 ? string()+m+m+m : "";
    }



// 0ms
    def largestGoodInteger(_, n):
        return next((d*3 for d in '9876543210' if d*3 in n), '')