C++ Tic-Tac-Toe: Check if Second Player Won - Algorithm & Code

Here is a possible solution in C++:\n\ncpp\n#include \<iostream>\n#include \<vector>\n#include \<string>\n\nusing namespace std;\n\nbool checkLine(const vector\<string> &board, int r, int c, int dr, int dc) {\n char symbol = board[r][c];\n for (int i = 0; i < 3; i++) {\n if (board[r][c] != symbol) {\n return false;\n }\n r += dr;\n c += dc;\n }\n return true;\n}\n\nbool checkWin(const vector\<string> &board) {\n // Check rows\n for (int r = 0; r < 3; r++) {\n if (checkLine(board, r, 0, 0, 1)) {\n return true;\n }\n }\n // Check columns\n for (int c = 0; c < 3; c++) {\n if (checkLine(board, 0, c, 1, 0)) {\n return true;\n }\n }\n // Check diagonals\n if (checkLine(board, 0, 0, 1, 1) || checkLine(board, 0, 2, 1, -1)) {\n return true;\n }\n return false;\n}\n\nint main() {\n int t;\n cin >> t;\n while (t--) {\n vector\<string> board(3);\n for (int i = 0; i < 3; i++) {\n cin >> board[i];\n }\n bool hasWin = checkWin(board);\n if (hasWin) {\n cout << "yes" << endl;\n } else {\n cout << "no" << endl;\n }\n }\n return 0;\n}\n\n\nExplanation:\n1. The checkLine function checks if there are three consecutive symbols in a row, column, or diagonal starting from a given position.\n2. The checkWin function checks if any of the rows, columns, or diagonals have three consecutive symbols of the same player.\n3. In the main function, we read the number of test cases t. For each test case, we read the game board and check if the second player (O) has won. We output "yes" if they have won, and "no" otherwise.