vault backup: 2022-07-22 16:03:37

OJ notes/pages/Leetcode Single-Number.md

@@ -22,7 +22,8 @@ tag:#bit_manipulation
 
 ##### Links:
 - [Link to problem](https://leetcode.com/problems/single-number/)
-- [Learn about XOR]()
+- [Learn about XOR](https://en.wikipedia.org/wiki/Exclusive_or#Computer_science)
+- [Explanation](https://leetcode.com/problems/single-number/discuss/1772139/C%2B%2Bor-Explained-Everything-w-WHY-XOR-WORKSor-BRUTE-FORCE-TO-OPTIMIZEDor-STEP-BY-STEP-DRY-RUN)
 ___
 ### Problem
 
@@ -59,5 +60,29 @@ You must implement a solution with a linear runtime complexity and use only co
 > This is a #bit_manipulation problem utilizing the XOR operator
 
 
+The XOR operator has some properties:
+
+```
+a ^ a = 0;
+a ^ b ^ a = a ^ a ^ b = b;
+```
+
+This can be used for our problem.
 
 ### Solution
+
+```cpp
+class Solution {
+public:
+  int singleNumber(vector<int> &nums) {
+    // Using XOR operator
+    int ans = 0;
+
+    for (int i : nums) {
+      ans ^= i;
+    }
+
+    return ans;
+  }
+};
+```