2864. Maximum Odd Binary Number

Description

You are given a binary string s that contains at least one '1'.

You have to rearrange the bits in such a way that the resulting binary number is the maximum odd binary number that can be created from this combination.

Return a string representing the maximum odd binary number that can be created from the given combination.

Note that the resulting string can have leading zeros.

 

Example 1:

Input: s = "010"
Output: "001"
Explanation: Because there is just one '1', it must be in the last position. So the answer is "001".

Example 2:

Input: s = "0101"
Output: "1001"
Explanation: One of the '1's must be in the last position. The maximum number that can be made with the remaining digits is "100". So the answer is "1001".

 

Constraints:

  • 1 <= s.length <= 100
  • s consists only of '0' and '1'.
  • s contains at least one '1'.

Solutions

Solution 1: Greedy

First, we count the number of ‘1’s in the string $s$, denoted as $cnt$. Then, we place $cnt - 1$ ‘1’s at the highest position, followed by the remaining $|s| - cnt$ ‘0’s, and finally add one ‘1’.

The time complexity is $O(n)$, and the space complexity is $O(n)$. Here, $n$ is the length of the string $s$.

Python Code
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class Solution:
    def maximumOddBinaryNumber(self, s: str) -> str:
        cnt = s.count("1")
        return "1" * (cnt - 1) + (len(s) - cnt) * "0" + "1"

Java Code
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class Solution {
    public String maximumOddBinaryNumber(String s) {
        int cnt = 0;
        for (char c : s.toCharArray()) {
            if (c == '1') {
                ++cnt;
            }
        }
        return "1".repeat(cnt - 1) + "0".repeat(s.length() - cnt) + "1";
    }
}

C++ Code
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class Solution {
public:
    string maximumOddBinaryNumber(string s) {
        int cnt = count_if(s.begin(), s.end(), [](char c) { return c == '1'; });
        string ans;
        for (int i = 1; i < cnt; ++i) {
            ans.push_back('1');
        }
        for (int i = 0; i < s.size() - cnt; ++i) {
            ans.push_back('0');
        }
        ans.push_back('1');
        return ans;
    }
};

Go Code
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func maximumOddBinaryNumber(s string) string {
	cnt := strings.Count(s, "1")
	return strings.Repeat("1", cnt-1) + strings.Repeat("0", len(s)-cnt) + "1"
}

TypeScript Code
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function maximumOddBinaryNumber(s: string): string {
    let cnt = 0;
    for (const c of s) {
        cnt += c === '1' ? 1 : 0;
    }
    return '1'.repeat(cnt - 1) + '0'.repeat(s.length - cnt) + '1';
}