add: 220326-CN [cpp]

cpp/2203/220326-CN.cpp

@@ -0,0 +1,47 @@
+#include <vector>
+#include <string>
+#include <numeric>
+#include <stdexcept>
+#include <algorithm>
+
+/**
+ * 682. Baseball Game
+ * You are keeping score for a baseball game with strange rules. The game consists of several rounds, where the scores of past rounds may affect future rounds' scores.
+ * At the beginning of the game, you start with an empty record. You are given a list of strings ops, where ops[i] is the ith operation you must apply to the record and is one of the following:
+ * - An integer x - Record a new score of x.
+ * - "+" - Record a new score that is the sum of the previous two scores. It is guaranteed there will always be two previous scores.
+ * - "D" - Record a new score that is double the previous score. It is guaranteed there will always be a previous score.
+ * - "C" - Invalidate the previous score, removing it from the record. It is guaranteed there will always be a previous score.
+ * Return the sum of all the scores on the record.
+ *
+ * 100% STL implementation!
+ */
+
+class Solution {
+public:
+	static int calPoints(std::vector<std::string>& ops) {
+		std::vector<int> scores;
+		std::for_each(ops.begin(), ops.end(), [&](const std::string& str) {
+			int x;
+			try {
+				x = std::stoi(str);
+			} catch (const std::invalid_argument& ignored) {
+				switch (str[0]) {
+					case '+':
+						scores.push_back(*std::prev(scores.end(), 2) + scores.back());
+						break;
+					case 'C':
+						scores.pop_back();
+						break;
+					case 'D':
+						scores.push_back(2 * scores.back());
+						break;
+					default:;
+				}
+				return;
+			}
+			scores.push_back(x);
+		});
+		return std::accumulate(scores.begin(), scores.end(), 0);
+	}
+};

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220326.cpp)
+ADD_EXECUTABLE(2203 220326-CN.cpp)