Shared code

#include <bits/stdc++.h> 
using namespace std;  

typedef long long ll;  
typedef pair<int, int> ii;  

const int INF = 1e9;  
const ll LINF = 1e18;  

const int N = 1e6 + 5;  

template<typename T>
bool minimize(T& a, const T& b) {
	if (a < b) return false;
	a = b; 
	return true; 
}

int memo[N];   

int dp(int n) {
	if (n == 0) return 0;  

	int& ans = memo[n]; 
	if (ans != -1) return ans;  

	ans = INF;      
	for (int tmp = n; tmp > 0; tmp /= 10) {
		int digit = tmp % 10; 
		minimize(ans, 1 + dp(n - digit)); 
	}

	return ans;  
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);  	
	int n; 
	cin >> n;   

	memset(memo, -1, sizeof memo); 

	cout << dp(n) << '\n'; 
}