1980. Find Unique Binary String

Description

Given an array of strings nums containing n unique binary strings each of length n, return a binary string of length n that does not appear in nums. If there are multiple answers, you may return any of them.

 

Example 1:

Input: nums = ["01","10"]
Output: "11"
Explanation: "11" does not appear in nums. "00" would also be correct.

Example 2:

Input: nums = ["00","01"]
Output: "11"
Explanation: "11" does not appear in nums. "10" would also be correct.

Example 3:

Input: nums = ["111","011","001"]
Output: "101"
Explanation: "101" does not appear in nums. "000", "010", "100", and "110" would also be correct.

 

Constraints:

• n == nums.length
• 1 <= n <= 16
• nums[i].length == n
• nums[i] is either '0' or '1'.
• All the strings of nums are unique.

 

Solutions

Solution: Backtracking

• Time complexity: O(n²)
• Space complexity: O(n)

 

JavaScript

/**
 * @param {string[]} nums
 * @return {string}
 */
const findDifferentBinaryString = function (nums) {
  const size = nums[0].length;
  const backtracking = (current = '') => {
    if (current.length === size) {
      if (nums.includes(current)) return '';
      return current;
    }
    const result = backtracking(`${current}0`);

    if (result) return result;
    return backtracking(`${current}1`);
  };

  return backtracking();
};