LeetCode_Spiral Matrix

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.



For example,

Given the following matrix:

[

 [ 1, 2, 3 ],

 [ 4, 5, 6 ],

 [ 7, 8, 9 ]

]

You should return [1,2,3,6,9,8,7,4,5].

　　注意几点： 1)spiral 总共转了几圈 2) 最后一圈的时候如果是“横”“竖”需要处理好边界

class Solution {

public:

    vector<int> spiralOrder(vector<vector<int> > &matrix) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

      　vector<int> res;

        int rows = matrix.size();

        if(rows == 0) return res;

        int columns = matrix[0].size();

        if( columns ==0) return res;



        int lays = rows > columns ? (columns+1)/2 : (rows+1) /2; 

        bool single =  rows > columns ? columns%2 :rows%2 ;

        for(int lay = 0; lay < lays ; lay++)

        {

            int topRow = lay;

            int rightColumn = columns  - 1 - lay;



            //process the top row 

            for(int i = lay ; i <= rightColumn ; i++)

                res.push_back(matrix[topRow][i]);

            //process the right column ,not include the first of the right column element 

            for(int i = lay +1 ; i <= rows - 1 - lay ; i++)

                res.push_back(matrix[i][rightColumn]);

            

            if(lay == lays -1 && single)

                 continue ;

            //process the bottom row, not include the last of the bottom row element

            for(int i = rightColumn - 1 ;i >= lay ; i--)

                res.push_back(matrix[rows-1-lay][i]);



            //process the left;

            for(int i = rows - 1 - lay -1  ;i > lay ; i--)

                res.push_back(matrix[i][lay]);



        }



        return res;

    }

};