add: 230412

cpp/2304/230412.cpp

@@ -0,0 +1,44 @@
+#include <string>
+
+/**
+ * 71. Simplify Path
+ * Given a string path, which is an absolute path (starting with a slash '/') to a file or directory in a Unix-style file system, convert it to the simplified canonical path.
+ *
+ * In a Unix-style file system, a period '.' refers to the current directory, a double period '..' refers to the directory up a level, and any multiple consecutive slashes (i.e. '//') are treated as a single slash '/'. For this problem, any other format of periods such as '...' are treated as file/directory names.
+ *
+ * The canonical path should have the following format:
+ *
+ * The path starts with a single slash '/'.
+ * Any two directories are separated by a single slash '/'.
+ * The path does not end with a trailing '/'.
+ * The path only contains the directories on the path from the root directory to the target file or directory (i.e., no period '.' or double period '..')
+ * Return the simplified canonical path.
+ */
+
+class Solution {
+public:
+	static std::string simplifyPath(const std::string&);
+};
+
+std::string Solution::simplifyPath(const std::string& path) {
+	char buf[3072]{};
+	int n = path.size(), ps = 0, pt = 1, prev = 0;
+	const char* ptr = path.c_str();
+	for (; pt <= n; ++pt) {
+		if (ptr[pt] && ptr[pt] != '/')
+			continue;
+		if (int diff = pt - prev; diff == 3 && ptr[pt - 1] == '.' && ptr[pt - 2] == '.') {
+			while (ps > 0 && buf[--ps] != '/');
+		} else if (diff > 2 || (diff == 2 && ptr[prev + 1] != '.')) {
+			buf[ps++] = '/';
+			for (int i = prev + 1; i < pt; buf[ps++] = ptr[i++]);
+		}
+		prev = pt;
+	}
+	return ps ? std::string(buf, buf + ps) : "/";
+}
+
+int main() {
+	auto r = Solution::simplifyPath("/a//b////c/d//././/..");
+	return 0;
+}

cpp/2304/CMakeLists.txt

@@ -4,4 +4,4 @@ PROJECT(2304)
 SET(CMAKE_CXX_STANDARD 23)
 SET(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-ADD_EXECUTABLE(2304 230411-CN.cpp)
+ADD_EXECUTABLE(2304 230412.cpp)