Write a program to solve a Sudoku puzzle by filling the empty cells.
Empty cells are indicated by the character '.'
You may assume that there will be only one unique solution.
A sudoku puzzle...
...and its solution numbers marked in red.
题意：求解一个数独，的完整解。
public void solveSudoku(char[][] board) {
solve(board);
}
private boolean solve(char[][] board){
for(int row = 0;row<9;row++){
for(int col = 0;col<9;col++){
if(board[row][col] == '.'){
for(char i = '1';i<='9';i++){
board[row][col] = i;
if(isValid(board,row,col) && solve(board))
return true;
board[row][col] = '.';
}
return false;
}
}
}
return true;
}
private boolean isValid(char[][] board,int row,int col){
for(int i = 0;i<9;i++){
if(i!=col && board[row][i] == board[row][col])
return false;
}
for(int i = 0;i<9;i++){
if(i!=row && board[i][col] == board[row][col])
return false;
}
int beginRow = 3*(row/3);
int beginCol = 3*(col/3);
for(int i = beginRow;i<beginRow+3;i++){
for(int j = beginCol;j<beginCol+3;j++){
if(i!=row && j!=col && board[i][j] == board[row][col])
return false;
}
}
return true;
}
