26. Partitioning Into Minimum Number Of Deci-Binary Numbers.cpp

/*
Partitioning Into Minimum Number Of Deci-Binary Numbers
==========================================================

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 <= 105
n consists of only digits.
n does not contain any leading zeros and represents a positive integer.

Hint #1  
Think about if the input was only one digit. Then you need to add up as many ones as the value of this digit.

Hint #2  
If the input has multiple digits, then you can solve for each digit independently, and merge the answers to form numbers that add up to that input.

Hint #3  
Thus the answer is equal to the max digit.
*/

class Solution
{
public:
  int minPartitions(string n)
  {
    int ans = 0;
    for (auto &i : n)
      ans = max(ans, i - '0');
    return ans;
  }
};