Deleting digits

input/code.cpp: In function 'void solve()':
input/code.cpp:13:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |         for (int i = 0; i < tempt.length(); i++) {
      |                         ~~^~~~~~~~~~~~~~~~

#include <bits/stdc++.h>
using namespace std;
 
const int MAXN = 1e5 + 1;
long long n;
long long res = 0;
 
void solve() {
    cin >> n;
    while (n > 0) {
        string tempt = to_string (n);
        int nu = 0; 
        for (int i = 0; i < tempt.length(); i++) {
            int num = tempt[i] - '0';
            if (num >= nu) nu = num;
        }
        //cout << nu << endl;
        n -= nu;
        res++;
    }
    
    cout << res;
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    solve();
 
    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