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Design a Tic-tac-toe game that is played between two players on a n x n grid.
Java Solution 1 – Naive
We can simply check the row, column, and diagonals and see if there is a winner.
public class TicTacToe {
int[][] matrix;
/** Initialize your data structure here. */
public TicTacToe(int n) {
matrix = new int[n][n];
}
/** 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. */
public int move(int row, int col, int player) {
matrix[row][col]=player;
//check row
boolean win=true;
for(int i=0; i<matrix.length; i++){
if(matrix[row][i]!=player){
win=false;
break;
}
}
if(win) return player;
//check column
win=true;
for(int i=0; i<matrix.length; i++){
if(matrix[i][col]!=player){
win=false;
break;
}
}
if(win) return player;
//check back diagonal
win=true;
for(int i=0; i<matrix.length; i++){
if(matrix[i][i]!=player){
win=false;
break;
}
}
if(win) return player;
//check forward diagonal
win=true;
for(int i=0; i<matrix.length; i++){
if(matrix[i][matrix.length-i-1]!=player){
win=false;
break;
}
}
if(win) return player;
return 0;
}
}
Java Solution 2
public class TicTacToe {
int[] rows;
int[] cols;
int dc1;
int dc2;
int n;
/** Initialize your data structure here. */
public TicTacToe(int n) {
this.n=n;
this.rows=new int[n];
this.cols=new int[n];
}
/** 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. */
public int move(int row, int col, int player) {
int val = (player==1?1:-1);
rows[row]+=val;
cols[col]+=val;
if(row==col){
dc1+=val;
}
if(col==n-row-1){
dc2+=val;
}
if(Math.abs(rows[row])==n
|| Math.abs(cols[col])==n
|| Math.abs(dc1)==n
|| Math.abs(dc2)==n){
return player;
}
return 0;
}
}