add: 220518 + CN [cpp]

cpp/2205/220518-CN.cpp

@@ -0,0 +1,42 @@
+#include <cstdio>
+
+/**
+ * 668. Kth Smallest Number in Multiplication Table
+ * Nearly everyone has used the Multiplication Table. The multiplication table of size m x n is an integer matrix mat where mat[i][j] == i * j (1-indexed).
+ * Given three integers m, n, and k, return the kth smallest element in the m x n multiplication table.
+ */
+
+class Solution {
+public:
+	static constexpr int findKthNumber(int m, int n, int k) {
+		auto compute = [&](int upper_bound) {
+			int ans = 0;
+			for (int i = 1; i <= m; ++i)
+				ans += (upper_bound / i <= n) ? (upper_bound / i) : n;
+			return ans;
+		};
+		int L = 1, R = m * n, M;
+
+		// [L, R]
+		while (L < R) {
+			M = (L + R) >> 1;
+			int x = compute(M);
+			if (x > k) {
+				R = M;
+			} else if (x < k) {
+				L = M + 1;
+			} else {
+				break;
+			}
+		}
+
+		M = (L + R + 1) >> 1;
+		for (int c = compute(M), p; (p = compute(M - 1)) >= k || p == c; --M);
+		return M;
+	}
+};
+
+int main() {
+	std::printf("%d\n", Solution::findKthNumber(2, 3 ,6));
+	return 0;
+}

cpp/2205/220518.cpp

@@ -1,6 +1,13 @@
 #include <vector>
 #include <functional>
 
+/**
+ * 1192. Critical Connections in a Network
+ * There are n servers numbered from 0 to n - 1 connected by undirected server-to-server connections forming a network where connections[i] = [ai, bi] represents a connection between servers ai and bi. Any server can reach other servers directly or indirectly through the network.
+ * A critical connection is a connection that, if removed, will make some servers unable to reach some other server.
+ * Return all critical connections in the network in any order.
+ */
+
 class Solution {
 public:
 	static std::vector<std::vector<int>> criticalConnections(int n, const std::vector<std::vector<int>>& e) {

cpp/2205/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2205)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2205 220518.cpp)
+ADD_EXECUTABLE(2205 220518-CN.cpp)