0348. Design Tic-Tac-Toe.md

348. Design Tic-Tac-Toe, medium, locked

Design a Tic-tac-toe game that is played between two players on a n x n grid.

You may assume the following rules:

A move is guaranteed to be valid and is placed on an empty block. Once a winning condition is reached, no more moves is allowed. A player who succeeds in placing n of their marks in a horizontal, vertical, or diagonal row wins the game.

// 28ms, 95%
class TicTacToe {
    vector<int> rows;
    vector<int> cols;
    int d1;
    int d2;
public:
    /** Initialize your data structure here. */
    TicTacToe(int n) {
        rows.resize(n, 0);
        cols.resize(n, 0);
        d1 = d2 = 0;
    }
    
    /** Player {player} makes a move at ({row}, {col}).
        @param row The row of the board.
        @param col The column of the board.
        @param player The player, can be either 1 or 2.
        @return The current winning condition, can be either:
                0: No one wins.
                1: Player 1 wins.
                2: Player 2 wins. */
    int move(int row, int col, int player) {
        const int N = rows.size();
        const int score = player == 1? 1:-1;
        rows[row] += score;
        cols[col] += score;
        if (row == col) d1 += score;
        if (row + col == N-1)
            d2 += score;

        const int WIN = score*N;
        return (rows[row] == WIN ||
           cols[col] == WIN ||
           d1 == WIN ||
           d2 == WIN)? player: 0;
            
    }
};

// 40ms, 40%
class TicTacToe {
    vector<vector<int>> board;
public:
    /** Initialize your data structure here. */
    TicTacToe(int n) {
        board.resize(n, vector<int>(n, 0));
    }
    
    /** Player {player} makes a move at ({row}, {col}).
        @param row The row of the board.
        @param col The column of the board.
        @param player The player, can be either 1 or 2.
        @return The current winning condition, can be either:
                0: No one wins.
                1: Player 1 wins.
                2: Player 2 wins. */
    int move(int row, int col, int player) {
        board[row][col] = player;
        int rcnt = 0, ccnt = 0, dcnt1 = 0, dcnt2 = 0;
        const int N = board.size();
        auto checkd1 = row == col;
        auto checkd2 = row + col == N - 1;
        for (int i = 0; i < N; i++) {
            rcnt += board[row][i] == player;
            ccnt += board[i][col] == player;
            if (checkd1) {
                dcnt1 += board[i][i] == player;
            }
            if (checkd2) {
                dcnt2 += board[N-i-1][i] == player;
            }
        }
        return rcnt == N || ccnt == N || dcnt1 == N || dcnt2 == N? player: 0;
    }
};

/**
 * Your TicTacToe object will be instantiated and called as such:
 * TicTacToe* obj = new TicTacToe(n);
 * int param_1 = obj->move(row,col,player);
 */