Deleting digits

#include <bits/stdc++.h>

int largest_digit(int i) {
    int max_digit = 0;
    while (i > 0) {
        max_digit = std::max(max_digit, i % 10);
        i /= 10;
    }
    return max_digit;
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n;
    std::cin >> n;

    int count = 0;
    while (n > 0) {
        n -= largest_digit(n);
        count++;
    }

    std::cout << count << std::endl;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED