54. Spiral Matrix 解题记录

题目描述：

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].

解题思路：

这题的思路没有什么好说的，就是一圈一圈添加元素进数组。只是要注意row和col是不一样的情况和相同时是偶数的情况。

代码：

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        vector<int> ret;
        if(matrix.size()==0)
            return ret;
        int row = matrix.size();
        int col = matrix[0].size();
        int times = row>col?col/2:row/2;
        for(int i = 0; i < times; i++){
            for(int j = i; j < col-1-i; j++)
                ret.push_back(matrix[i][j]);
            for(int j = i; j < row-1-i; j++)
                ret.push_back(matrix[j][col-1-i]);
            for(int j = col-1-i; j > i; j--)
                ret.push_back(matrix[row-1-i][j]);
            for(int j = row-1-i; j > i; j--)
                ret.push_back(matrix[j][i]);
        }
        int mod = row>col?col%2:row%2;
        if(mod == 1){
            if(row == col)
                ret.push_back(matrix[times][times]);
            else if(col > row)
                for(int i = times; i < col-times; i++)
                    ret.push_back(matrix[times][i]);
            else
                for(int i = times; i < row-times; i++)
                    ret.push_back(matrix[i][times]);
        }
        return ret;
    }
};