LeetCode OJ:Sudoku Solver

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Sudoku Solver

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.

算法思想：

暴力深搜

class Solution {        int map[10][10];//预先赋值的数组用来判断第i行第j列是第几个九宫格    bool r[10][10];//r[i][j]表示第i行是否已经有j了，如果有了就为true否则是false    bool c[10][10];//c[i][j]表示第i列是否已经有j了，如果有了就为true否则是false    bool s[10][10];//s[i][j]表示第i个九宫格中是否已经有j了，如果有了就为true否则是false（九宫格排序按从上到下从左到右）    int counts, p[100], q[100];//counts记录的是一共有多少个格子没有填数字，p数组记录他们的行序号，q数组记录他们的列序号    //bool flag;//记录搜索的状态，如果找到答案了就为true，没找到为falsepublic:    void MakeMap()    {    for(int i = 1; i <= 9; i++)    {    for(int j = 1; j <= 9; j++)    {    if(i <= 3)    {    if(j <= 3)    map[i][j] = 1;    else if(j <= 6)    map[i][j] = 2;    else    map[i][j] = 3;    }    else if(i <= 6)    {    if(j <= 3)    map[i][j] = 4;    else if(j <= 6)    map[i][j] = 5;    else    map[i][j] = 6;    }    else    {    if(j <= 3)    map[i][j] = 7;    else if(j <= 6)    map[i][j] = 8;    else    map[i][j] = 9;    }    }    }    }    void initial(vector<vector<char>> &board){        counts=0;memset(r,false,sizeof(r));memset(c,false,sizeof(c));memset(s,false,sizeof(s));        for(int i = 1; i <= 9; i++){for(int j = 1; j <= 9; j++){if(board[i-1][j-1] != '.'){r[i][board[i-1][j-1]-'0'] = true;c[j][board[i-1][j-1]-'0'] = true;s[map[i][j]][board[i-1][j-1]-'0'] = true;}else//记录没有填数字的格子{counts++;p[counts] = i;q[counts] = j;}}}    }    bool DFS(int cur,vector<vector<char>> &board)    {    if(cur == counts + 1)    {    return true;    }    for(int i = 1; i <= 9; i++)//p[cur]表示未填数字的格子的行序号，q[cur]表示未填数字的格子的列序号    {    if(r[p[cur]][i] == false && c[q[cur]][i] == false && s[map[p[cur]][q[cur]]][i] == false)    {    board[p[cur]-1][q[cur]-1] = i + '0';    r[p[cur]][i] = true;    c[q[cur]][i] = true;    s[map[p[cur]][q[cur]]][i] = true;    if(DFS(cur + 1 , board))return true;    //board[p[cur]-1][q[cur]-1] = '.';    r[p[cur]][i] = false;    c[q[cur]][i] = false;    s[map[p[cur]][q[cur]]][i] = false;    }    }    }    void solveSudoku(vector<vector<char> > &board) {        MakeMap();//map矩阵的初始化        initial(board);//初始化操作        DFS(1,board);    }};

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