add: 220616-CN

cpp/2206/220616-CN.cpp

@@ -0,0 +1,40 @@
+#include <vector>
+#include <unordered_set>
+#include <unordered_map>
+
+/**
+ * 532. K-diff Pairs in an Array
+ * Given an array of integers nums and an integer k, return the number of unique k-diff pairs in the array.
+ * A k-diff pair is an integer pair (nums[i], nums[j]), where the following are true:
+ * - 0 <= i, j < nums.length
+ * - i != j
+ * - nums[i] - nums[j] == k
+ * Notice that |val| denotes the absolute value of val.
+ *
+ * Refer: 220209.cpp
+ */
+
+class Solution {
+public:
+	static int findPairs(const std::vector<int>& nums, int k) {
+		int ans = 0;
+		if (k) {
+			std::unordered_set<int> s;
+			for (int i : nums) {
+				if (s.count(i))
+					continue;
+				if (s.count(i + k))
+					++ans;
+				if (s.count(i - k))
+					++ans;
+				s.insert(i);
+			}
+		} else {
+			std::unordered_map<int, int> m;
+			for (int i : nums)
+				if (m[i]++ == 1)
+					++ans;
+		}
+		return ans;
+	}
+};

cpp/2206/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2206)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2206 220615-CN.cpp)
+ADD_EXECUTABLE(2206 220616-CN.cpp)