add: 221026

cpp/2210/221026.cpp

@@ -0,0 +1,39 @@
+#include <unordered_set>
+#include <vector>
+#include <iostream>
+
+/**
+ * 523. Continuous Subarray Sum
+ *
+ * Given an integer array nums and an integer k, return true if nums has a continuous subarray of size at least two whose elements sum up to a multiple of k, or false otherwise.
+ * An integer x is a multiple of k if there exists an integer n such that x = n * k. 0 is always a multiple of k.
+ */
+
+class Solution {
+public:
+	static bool checkSubarraySum(const std::vector<int>& nums, int k) {
+		int sum = nums[0] % k, n = nums.size(), prev = 0;
+		if (n < 2)
+			return false;
+		if (k == 1)
+			return true;
+		if (n == 2)
+			return (nums[0] + nums[1]) % k == 0;
+		std::unordered_set<int> s{0, nums[0] % k};
+		for (int i = 1; i < n; ++i) {
+			if (!(nums[i] % k) && !(nums[i - 1] % k))
+				return true;
+			prev = sum;
+			sum = (sum + nums[i]) % k;
+			if (s.count(sum) && prev != sum)
+				return true;
+			s.insert(sum);
+		}
+		return false;
+	}
+};
+
+int main() {
+	std::cout << Solution::checkSubarraySum({1,2,12}, 6);
+	return 0;
+}

cpp/2210/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2210)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2210 221026-CN.cpp)
+ADD_EXECUTABLE(2210 221026.cpp)