企业官网建设流程全解析

1275. Find Winner on a Tic Tac Toe Game

Tic-tac-toe is played by two players A and B on a 3 x 3 grid. The rules of Tic-Tac-Toe are:

• Players take turns placing characters into empty squares ’ '.
• The first player A always places ‘X’ characters, while the second player B always places ‘O’ characters.
• ‘X’ and ‘O’ characters are always placed into empty squares, never on filled ones.
• The game ends when there are three of the same (non-empty) character filling any row, column, or diagonal.
• The game also ends if all squares are non-empty.
• No more moves can be played if the game is over.

Given a 2D integer array moves wherem o v e s [ i ] = [ r o w i , c o l i ] moves[i] = [row_i, col_i]moves[i]=[rowi​,coli​]indicates that thei t h i^{th}ithmove will be played ong r i d [ r o w i ] [ c o l i ] grid[row_i][col_i]grid[rowi​][coli​]. return the winner of the game if it exists (A or B). In case the game ends in a draw return “Draw”. If there are still movements to play return “Pending”.

You can assume that moves is valid (i.e., it follows the rules of Tic-Tac-Toe), the grid is initially empty, and A will play first.

Example 1:

Input:moves = [[0,0],[2,0],[1,1],[2,1],[2,2]]
Output:“A”
Explanation:A wins, they always play first.

Example 2:

Input:moves = [[0,0],[1,1],[0,1],[0,2],[1,0],[2,0]]
Output:“B”
Explanation:TB wins.

Example 3:

Input:moves = [[0,0],[1,1],[2,0],[1,0],[1,2],[2,1],[0,1],[0,2],[2,2]]
Output:“Draw”
Explanation:The game ends in a draw since there are no moves to make.

Constraints:

• 1 <= moves.length <= 9
• moves[i].length == 2
• 0 < = r o w i , c o l i < = 2 0 <= row_i, col_i <= 20<=rowi​,coli​<=2
• There are no repeated elements on moves.
• moves follow the rules of tic tac toe.

From: LeetCode
Link: 1275. Find Winner on a Tic Tac Toe Game

Solution:

Ideas:

put A as 1, B as -1.
If any row, column, or diagonal sums to 3, A wins.
If it sums to -3, B wins.

Code:

char*tictactoe(int**moves,intmovesSize,int*movesColSize){intboard[3][3]={0};// A = 1, B = -1for(inti=0;i<movesSize;i++){intr=moves[i][0];intc=moves[i][1];board[r][c]=(i%2==0)?1:-1;}for(inti=0;i<3;i++){introw=board[i][0]+board[i][1]+board[i][2];intcol=board[0][i]+board[1][i]+board[2][i];if(row==3||col==3)return"A";if(row==-3||col==-3)return"B";}intdiag1=board[0][0]+board[1][1]+board[2][2];intdiag2=board[0][2]+board[1][1]+board[2][0];if(diag1==3||diag2==3)return"A";if(diag1==-3||diag2==-3)return"B";if(movesSize==9)return"Draw";return"Pending";}