LeetCode Entry

1295. Find Numbers with Even Number of Digits

30.04.2025 easy 2025 kotlin rust

Even length numbers

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Problem TLDR

Even length numbers #easy

Intuition

Do what is asked

Approach

  • some golf and counter acrobatics possible
  • how the input range can be used?

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(1)\)

Code


// 3ms
    fun findNumbers(n: IntArray) =
    n.count { "$it".length % 2 < 1 }



// 1ms
    fun findNumbers(n: IntArray) = n
    .count { it in 10..99 || it in 1000..9999 || it == 100000 }



// 0ms
    pub fn find_numbers(n: Vec<i32>) -> i32 {
        n.iter().map(|&x| { let (mut x, mut c) = (x, 1);
            while x > 0 { x /= 10; c = 1 - c }; c
        }).sum()
    }



// 0ms
    int findNumbers(vector<int>& n) {
        int r = 0;
        for (int c = 0; int x: n)
            for (c = 1, r++; x > 0; x /= 10 ) r +=  2 * (++c & 1) - 1;
        return r;
    }