Leetcode题解（十三）

36、Valid Sudoku

题目

代码如下：

class Solution {
public:
    bool isValidSudoku(vector<vector<char> > &board) {
        // Note: The Solution object is instantiated only once.
        vector<vector<bool>> rows(9, vector<bool>(9,false));
        vector<vector<bool>> cols(9, vector<bool>(9,false));
        vector<vector<bool>> blocks(9, vector<bool>(9,false));

        for(int i = 0; i < 9; i++)
            for(int j = 0; j < 9; j++)
            {
                if(board[i][j] == '.')continue;
                int num = board[i][j] - '1';
                if(rows[i][num] || cols[j][num] || blocks[i - i%3 + j/3][num])
                    return false;
                rows[i][num] = cols[j][num] = blocks[i - i%3 + j/3][num] = true;
            }
        return true;
    }
};

 -------------------------------------------------------------------------------------------分割线---------------------------------------------------------------------------------

38、Count and Say

题目

找规律题目，直接上代码：

class Solution {
public:
   string unguarded_convert(const string &say)
{
    stringstream ss;
    int count = 0;
    char last = say[0];
    
    for (size_t i = 0; i <= say.size(); ++i)
    {
        if (say[i] == last)
        {
            ++count;
        }
        else
        {
            ss << count << last;
            count = 1;
            last = say[i];
        }
    }
    
    return ss.str();
}
 
string countAndSay(int n) 
{
    if (n <= 0) return string();
    
    string say = "1";
    
    for (int i = 1; i < n; ++i)
    {
        say = unguarded_convert(say);
    }
    
    return say;
}
};