add: 220412 [cpp]

cpp/2204/220412.cpp

@@ -0,0 +1,43 @@
+#include <vector>
+
+/**
+ * 289. Game of Life
+ * According to Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970."
+ *
+ * The board is made up of an m x n grid of cells, where each cell has an initial state: live (represented by a 1) or dead (represented by a 0). Each cell interacts with its eight neighbors (horizontal, vertical, diagonal) using the following four rules (taken from the above Wikipedia article):
+ *
+ * Any live cell with fewer than two live neighbors dies as if caused by under-population.
+ * Any live cell with two or three live neighbors lives on to the next generation.
+ * Any live cell with more than three live neighbors dies, as if by over-population.
+ * Any dead cell with exactly three live neighbors becomes a live cell, as if by reproduction.
+ * The next state is created by applying the above rules simultaneously to every cell in the current state, where births and deaths occur simultaneously. Given the current state of the m x n grid board, return the next state.
+ */
+
+class Solution {
+public:
+	static void gameOfLife(std::vector<std::vector<int>>& board) {
+		int m = board.size(), n = board.front().size();
+		auto GetIfValid = [&](int x, int y) {
+			return (x >= 0 && y >= 0 && x < m && y < n) ? board[x][y] & 1 : 0;
+		};
+		for (int i = 0; i < m; ++i) {
+			for (int j = 0; j < n; ++j) {
+				int c = -board[i][j];
+				for (int di = -1; di <= 1; ++di)
+					for (int dj = -1; dj <= 1; ++dj)
+						c += GetIfValid(i + di, j + dj);
+				switch (c) {
+					case 2:
+						if (!(board[i][j] & 1))
+							break;
+					case 3:
+						board[i][j] |= 2;
+					default:;
+				}
+			}
+		}
+		for (auto& i : board)
+			for (auto& j : i)
+				j >>= 1;
+	}
+};

cpp/2204/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2204)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2204 220412-CN.cpp)
+ADD_EXECUTABLE(2204 220412.cpp)