# Solution for Tic-Tac-Toe Runtime of Move function: O(1)

• The runtime of the move function of this solution is constant. It does not depend on the value of n.
The concept of the solution is fairly simple - Each move only affects only a specific column/row or two diagonal for that player only. If you know the total move count of that player for those four places ( that row, that column, and the two diagonals) then you can come to a conclusion that whether that player wins or not.

``````class TicTacToe {
int[][] hstatus; //contains the total move count for each player for each row.
int[][] vstatus; //contains the total move count for each player for each column.
int[][] dstatus; //contains the total move count for each player for both diagonal.
int n = 0; //size of the board.

/** Initialize your data structure here. */
public TicTacToe(int n) {
this.n = n;
hstatus= new int[2][n];
vstatus= new int[2][n];
dstatus = new int[2][2];
}

/** 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) {
// update the count for the row which is effected by the move
hstatus[player-1][row]++;
if(hstatus[player-1][row] == n) { //if entire row contains the player's moves then he wins
return player;
}

// update the count for the vertical column which is effected by the move
vstatus[player-1][col]++;
if(vstatus[player-1][col] == n) {  //if entire column contains players move then he wins
return player;
}
if(row == col) {   // if this is on top-left to bottom-right diagonal position.
dstatus[player-1][0]++;
if(dstatus[player-1][0] == n) {
return player;
}
}

if(row == n-col-1) { // if this is on bottom-left to top-right diagonal position.
dstatus[player-1][1]++;
if(dstatus[player-1][1] == n) {
return player;
}
}
return 0;
}
}

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

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