main.cpp

// Source: https://leetcode.com/problems/partitioning-into-minimum-number-of-deci-binary-numbers
// Title: Partitioning Into Minimum Number Of Deci-Binary Numbers
// Difficulty: Medium
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// A decimal number is called **deci-binary** if each of its digits is either `0` or `1` without any leading zeros. For example, `101` and `1100` are **deci-binary**, while `112` and `3001` are not.
//
// Given a string `n` that represents a positive decimal integer, return the **minimum** number of positive **deci-binary** numbers needed so that they sum up to `n`.
//
// **Example 1:**
//
// ```
// Input: n = "32"
// Output: 3
// Explanation: 10 + 11 + 11 = 32
// ```
//
// **Example 2:**
//
// ```
// Input: n = "82734"
// Output: 8
// ```
//
// **Example 3:**
//
// ```
// Input: n = "27346209830709182346"
// Output: 9
// ```
//
// **Constraints:**
//
// - `1 <= n.length <= 10^5`
// - `n` consists of only digits.
// - `n` does not contain any leading zeros and represents a positive integer.
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <algorithm>
#include <string>

using namespace std;

// Find the maximum digit in n.
class Solution {
 public:
  int minPartitions(const string &n) {
    if (n.empty()) return 0;

    return *max_element(n.cbegin(), n.cend()) - '0';
  }
};