[leetcode] 【数组】36. Valid Sudoku

Determine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.

The Sudoku board could be partially filled, where empty cells are filled with the character ‘.’.

A partially filled sudoku which is valid.

Note:
A valid Sudoku board (partially filled) is not necessarily solvable. Only the filled cells need to be validated.

题意

检测所给数独库是否符合数独游戏要求。
数独要求每个九宫格放1-9个数，不能重复。每行每列也要满足这个要求。

题解

无非是遍历每行每列以及每个九宫格。

//cpp//时间复杂度O(n^2)，空间复杂度O(1)class Solution {public:    bool isValidSudoku(vector<vector<char>>& board) {        for(int i=0;i!=9;i+=3)        {            for(int j=0;j!=9;j+=3)            {                if(!check1(board,i,j))                    return false;            }        }        for(int i=0;i!=9;i++)        {            if(!check2(board,i,0))                return false;        }        for(int i=0;i!=9;i++)        {            if(!check3(board,0,i))                return false;        }        return true;    }    bool check1(vector<vector<char>>& board,int row,int col)    {        int temp[10]={0};        for(int i=row;i!=row+3;i++)        {            for(int j=col;j!=col+3;j++)            {                if(board[i][j]!='.')                {                    int n=board[i][j]-'0';                    if(temp[n]>=1)                        return false;                    else temp[n]++;                }            }        }        return true;    }    bool check2(vector<vector<char>>& board,int row,int col)    {        int temp[10]={0};        for(int i=0;i!=9;i++)        {            if(board[row][i]!='.')            {                int n=board[row][i]-'0';                if(temp[n]>=1)                    return false;                else temp[n]++;            }        }        return true;    }    bool check3(vector<vector<char>>& board,int row,int col)    {        int temp[10]={0};        for(int i=0;i!=9;i++)        {            if(board[i][col]!='.')            {                int n=board[i][col]-'0';                if(temp[n]>=1)                    return false;                else temp[n]++;            }        }        return true;    }};