# LeetCode: Sudoku Solver, leetcodesudoku

Source: Internet
Author: User

LeetCode: Sudoku Solver, leetcodesudoku

Sudoku Solver Total Accepted: 13937 Total Submissions: 66832My Submissions

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.

`public class Solution {    public void solveSudoku(char[][] board) {           solve(board);           }    private boolean solve(char[][] board) {         for (int i = 0; i < 9; i++) {            for (int j = 0; j < 9; j ++) {                if (board[i][j] =='.') {                    for (char k = '1'; k <= '9'; k++) {                        board[i][j] = k;                        if (isValid(board, i, j) && solve(board)) {                            return true;                        }                        board[i][j] = '.';                    }                    return false;                }            }        }        return true;    }    private boolean isValid(char[][] board,int x, int y ) {        boolean [][] square = new boolean[9][9];        for (int i = 0; i < 9; i++) {            if (y != i &&board[x][y] == board[x][i]){                return false;            }        }        for (int i = 0; i < 9; i++) {            if (x != i &&board[i][y] == board[x][y]){                return false;            }        }        for (int i = (x / 3) * 3; i < (x / 3) * 3 + 3; i++) {            for (int j = (y /3) * 3; j < (y / 3) *3 + 3; j++) {                if (x != i && y != j && board[i][j] == board[x][y]) {                    return false;                }            }        }        return true;    }    }`
This question is more intentional. The first time it was done, it was used to judge the generated position of each location. It was done on ECLIPSE, But it timed out on OJ.

Then I thought of it. I don't need to judge the entire matrix. I just need to judge whether the word with the changed position meets the requirements!

October 11

Www. sudoku. name/index-cn.php

This helps you calculate

Related Keywords:

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