Deleting digits

#include <bits/stdc++.h>
 
using namespace std;
 
//Definitions for quicker writing
#define REP(i,a,b) for (int i = a; i < b; i++)
 
//Typedefs for quicker writing
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pi;
 
 
int main() {
    	//IO optimization
	ios::sync_with_stdio(0);
	cin.tie(0);
 
    	//Input definition
    	int n;
    	cin >> n;
	
	int num = n;
	int step = 0;
	//Main Part
	while(num > 0){
		int cur = num;
		int mx = 0;
		int dig;
		dig = cur % 10;
		mx = max(mx, dig);
		while(cur >= 10){
			cur /= 10;
			dig = cur % 10;
			mx = max(mx, dig);
		}
		num -= mx;
		step++;
	}
 
 
	//Output
	cout << step << "\n";
 
	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