add

Author: kamyu104

C++/single-element-in-a-sorted-array.cpp

@@ -0,0 +1,21 @@
+// Time:  O(logn)
+// Space: O(1)
+
+class Solution {
+public:
+    int singleNonDuplicate(vector<int>& nums) {
+        int left = 0, right = nums.size() - 1;
+        while (left <= right) {
+            auto mid = left + (right - left) / 2;
+            if (!(mid % 2 == 0 && mid + 1 < nums.size() &&
+                  nums[mid] == nums[mid + 1]) &&
+                !(mid % 2 == 1 && nums[mid] == nums[mid - 1])) {
+                right = mid - 1;
+            } else {
+                left = mid + 1;
+            }
+        }
+        return nums[left];
+    }
+};
+