From 04cd4258003d4588a5ea1d20e4e09bfda73798ea Mon Sep 17 00:00:00 2001
From: Lam Haoyin <root@eatswap.org>
Date: Thu, 3 Feb 2022 13:16:24 +0800
Subject: [PATCH] add: 220203

---
 2202/220203.cpp     | 25 +++++++++++++++++++++++++
 2202/CMakeLists.txt |  2 +-
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 2202/220203.cpp

diff --git a/2202/220203.cpp b/2202/220203.cpp
new file mode 100644
index 0000000..f237c84
--- /dev/null
+++ b/2202/220203.cpp
@@ -0,0 +1,25 @@
+#include <vector>
+#include <cstdio>
+#include <unordered_map>
+
+class Solution {
+public:
+	static int fourSumCount(const std::vector<int>& nums1, const std::vector<int>& nums2, const std::vector<int>& nums3, const std::vector<int>& nums4) {
+		int ret = 0;
+		std::unordered_map<int, int> m1, m2;
+		for (int i : nums1)
+			for (int j : nums2)
+				++m1[i + j];
+		for (int i : nums3)
+			for (int j : nums4)
+				++m2[i + j];
+		for (const auto& p : m1)
+			ret += p.second * m2[-p.first];
+		return ret;
+	}
+};
+
+int main() {
+	std::printf("%d\n", Solution::fourSumCount({0}, {0}, {0}, {0}));
+	return 0;
+}
diff --git a/2202/CMakeLists.txt b/2202/CMakeLists.txt
index 5b90e21..cecb085 100644
--- a/2202/CMakeLists.txt
+++ b/2202/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2202)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2202 220202.cpp)
+ADD_EXECUTABLE(2202 220203.cpp)