add: 230318-CN

cpp/2303/230318-CN.cpp

@@ -0,0 +1,95 @@
+#include <string>
+
+/**
+ * 1616. Split Two Strings to Make Palindrome
+ *
+ * You are given two strings a and b of the same length. Choose an index and split both strings at the same index, splitting a into two strings: aprefix and asuffix where a = aprefix + asuffix, and splitting b into two strings: bprefix and bsuffix where b = bprefix + bsuffix. Check if aprefix + bsuffix or bprefix + asuffix forms a palindrome.
+ * When you split a string s into sprefix and ssuffix, either ssuffix or sprefix is allowed to be empty. For example, if s = "abc", then "" + "abc", "a" + "bc", "ab" + "c" , and "abc" + "" are valid splits.
+ * Return true if it is possible to form a palindrome string, otherwise return false.
+ * Notice that x + y denotes the concatenation of strings x and y.
+ */
+
+class Solution {
+public:
+	static bool checkPalindromeFormation(const std::string& a, const std::string& b) {
+		const int m = a.length(), n = b.length();
+		if (m == 1 || n == 1)
+			return true;
+
+		// prefix[shorter](b) + suffix[longer](a)
+		// prefix b, base a
+		if (n >= ((m >> 1) + (m & 1))) {
+			bool OK = true;
+			// prefix (i) operates on a first and optionally switches to b
+			// suffix (j) always operates on a
+			for (int i = (m >> 1) - !(m & 1), j = m >> 1, switched = 0; i >= 0; --i, ++j) {
+				if ((switched ? b : a)[i] == a[j])
+					continue;
+				switched = 1;
+				if (b[i] == a[j])
+					continue;
+				OK = false;
+				break;
+			}
+			if (OK) return true;
+		}
+
+		// prefix(a) + suffix(b)
+		// prefix a, base b
+		if (m >= ((n >> 1) + (n & 1))) {
+			bool OK = true;
+			for (int i = (n >> 1) - !(n & 1), j = m >> 1, switched = 0; i >= 0; --i, ++j) {
+				if ((switched ? a : b)[i] == b[j])
+					continue;
+				switched = 1;
+				if (a[i] == b[j])
+					continue;
+				OK = false;
+				break;
+			}
+			if (OK) return true;
+		}
+
+		// prefix a, base a
+		if (n >= m) {
+			bool OK = true;
+			for (int i = (m >> 1) - !(m & 1), j = m >> 1, switched = 0; i >= 0; --i, ++j) {
+				if (((switched |= (j >= m)) ? b : a)[j] == a[i])
+					continue;
+				switched = 1;
+				if (a[i] == b[j])
+					continue;
+				OK = false;
+				break;
+			}
+			if (OK) return true;
+		}
+
+		// prefix b, base b
+		if (m >= n) {
+			bool OK = true;
+			for (int i = (n >> 1) - !(n & 1), j = m >> 1, switched = 0; i >= 0; --i, ++j) {
+				if (((switched |= (j >= n)) ? a : b)[j] == b[i])
+					continue;
+				switched = 1;
+				if (b[i] == a[j])
+					continue;
+				OK = false;
+				break;
+			}
+			if (OK) return true;
+		}
+
+		// can NEVER reach here
+		return false;
+	}
+};
+
+int main() {
+	bool ans = Solution::checkPalindromeFormation(
+		"aejbaalflrmkswrydwdkdwdyrwskmrlfqizjezd",
+		"uvebspqckawkhbrtlqwblfwzfptanhiglaabjea"
+	);
+	std::printf(ans ? "true" : "false");
+	return 0;
+}

cpp/2303/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2303)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2303 230317.cpp)
+ADD_EXECUTABLE(2303 230318-CN.cpp)