
Problem Statement
The task is to determine the minimum number of positive decimal numbers, each digit of which can only be 0 or 1, such that their sum equals the value represented by a given string n
. These special kinds of decimal numbers are referred to as deci-binary. For example, 101
and 1100
are valid deci-binary numbers, while numbers like 112
and 3001
are not because they contain digits greater than 1.
The string n
is a positive integer and doesn't contain any leading zeros. Our objective is to split this given number into the smallest number of deci-binary numbers.
Examples
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.
Approach and Intuition
To solve this problem, we need to understand:
Nature of Deci-binary numbers: Since each digit in a deci-binary number is
0
or1
, each deci-binary number can only contribute a1
at most to any single digit in the sum.Working with digit places individually: The greatest digit in the number
n
essentially dictates the minimum number of deci-binary numbers required; this is because to match this highest digit, one would need an equivalent number of1
s in that particular digit position across potentially multiple deci-binary numbers.
Here’s the intuition based on the example n = "82734"
:
- The maximum digit in "82734" is 8.
- Thus, at least 8 deci-binary numbers (all contributing a
1
at the place of the digit 8) are needed to build the number using a sum of deci-binary numbers.
By evaluating the maximum digit in the string n
, we can directly deduce the minimum number of deci-binary numbers required. Each of these numbers contributes at least once in each required place, ensuring they all sum up to the original number. By following the details in the examples
, insights into forming such a solution are showcased clearly.
Solutions
- C++
class Solution {
public:
int countMinPartitions(string num) {
return *max_element(begin(num), end(num)) - '0';
}
};
The problem involves finding the minimum number of deci-binary numbers required to partition a given string representing a non-negative integer. A deci-binary number is one where each digit can be either 0 or 1. The solution requires calculating the largest digit in the string, as this represents the minimum number of deci-binary numbers needed.
The solution, implemented in C++, creates a function countMinPartitions
which accepts the number as a string. Using the STL function max_element
, which is called with the string's beginning and end iterators, the maximal character (digit) in the string is identified. By subtracting the ASCII value of '0' from this character, the function efficiently calculates and returns the integer value of the maximum digit.
This method takes advantage of simple character arithmetic and standard library functions for a concise and efficient solution to the problem.
- Java
class Solution {
public int minNumberNeeded(String digits) {
int finalMax = 0;
for (int j = 0; j < digits.length(); j++) {
finalMax = Math.max(finalMax, digits.charAt(j) - '0');
}
return finalMax;
}
}
The given Java program defines a method within a Solution
class for determining the minimum number of deci-binary numbers needed to represent any non-negative integer n
described in a string digits
. Deci-binary numbers are composed of the digits 0
to 9
, but each digit in the number can only be 0
or 1
.
Review the steps that the method minNumberNeeded
performs:
Initialize
finalMax
to 0, which will store the largest single digit from the input stringdigits
.Iterate through each character in the string
digits
. For each character:- Convert the character to its numerical equivalent.
- Update
finalMax
to be the maximum value betweenfinalMax
and the numeric value of the current character.
After completing the loop, return
finalMax
. This returned value represents the minimum number of deci-binary numbers needed, as each deci-binary addition contributes to building the maximum single digit present in the string.
This method effectively finds the highest digit in the input string and uses that as the minimum number of deci-binary numbers required, since a deci-binary number contributes a maximum of 1
at any decimal place.
- Python
class Minimizer:
def minimalDecompose(self, digits: str) -> int:
return int(max(digits))
The provided Python solution effectively resolves the problem of determining the minimum number of deci-binary numbers needed to sum up to each digit of the given number string. Deci-binary numbers use only the digits 0 and 1. The approach taken in this code involves the following steps:
- Define a class named
Minimizer
. - Implement the
minimalDecompose
method that:- Accepts a string
digits
as its argument. - Returns the maximum digit when this string is converted to its integer form.
- Accepts a string
Here’s a quick breakdown of how the solution works:
- Once the
minimalDecompose
method is called, it receives a string of digits. - It converts each character of this string into an integer and identifies the highest number among them.
- This highest digit is the minimum count of deci-binary numbers required to compose the original number through component addition.
This approach directly determines the minimal number necessary by utilizing Python’s built-in max()
function that effortlessly identifies the maximum within the iterable supplied in this case, a string of digits.
By focusing on the example of a given input "82735", the max()
function isolates '8' as the largest digit. Therefore, at least eight deci-binary additions are required to replicate the number "82735" in a deci-binary sum. Hence, the function returns 8.
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