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2546. Apply Bitwise Operations to Make Strings Equal

Description

You are given two 0-indexed binary strings s and target of the same length n. You can do the following operation on s any number of times:

  • Choose two different indices i and j where 0 <= i, j < n.
  • Simultaneously, replace s[i] with (s[i] OR s[j]) and s[j] with (s[i] XOR s[j]).

For example, if s = "0110", you can choose i = 0 and j = 2, then simultaneously replace s[0] with (s[0] OR s[2] = 0 OR 1 = 1), and s[2] with (s[0] XOR s[2] = 0 XOR 1 = 1), so we will have s = "1110".

Return true if you can make the string s equal to target, or false otherwise.

 

Example 1:

 Input: s = "1010", target = "0110" Output: true Explanation: We can do the following operations: - Choose i = 2 and j = 0. We have now s = "0010". - Choose i = 2 and j = 1. We have now s = "0110". Since we can make s equal to target, we return true. 

Example 2:

 Input: s = "11", target = "00" Output: false Explanation: It is not possible to make s equal to target with any number of operations. 

 

Constraints:

  • n == s.length == target.length
  • 2 <= n <= 105
  • s and target consist of only the digits 0 and 1.

Solutions

Solution 1: Lateral Thinking

We notice that $1$ is actually a “tool” for number conversion. Therefore, as long as both strings either have $1$ or neither have $1$, we can make the two strings equal through operations.

The time complexity is $O(n)$, where $n$ is the length of the string. The space complexity is $O(1)$.

  • class Solution { public boolean makeStringsEqual(String s, String target) { return s.contains("1") == target.contains("1"); } } 
  • class Solution { public: bool makeStringsEqual(string s, string target) { auto a = count(s.begin(), s.end(), '1') > 0; auto b = count(target.begin(), target.end(), '1') > 0; return a == b; } }; 
  • class Solution: def makeStringsEqual(self, s: str, target: str) -> bool: return ("1" in s) == ("1" in target) 
  • func makeStringsEqual(s string, target string) bool { return strings.Contains(s, "1") == strings.Contains(target, "1") } 
  • function makeStringsEqual(s: string, target: string): boolean { return s.includes('1') === target.includes('1'); } 
  • impl Solution { pub fn make_strings_equal(s: String, target: String) -> bool { s.contains('1') == target.contains('1') } } 

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