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export default function countDigitOne(n: number): number {    let count = 0;
    for (let i = 1; i <= n; i *= 10) {        const divide = i * 10;        const p = Math.floor(n / divide),            k = n % divide;        let rest = 0;
        count += p * i;        rest = k > 2 * i - 1 ? i : k < i ? 0 : k - i + 1;        count += rest;    }    return count;}