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].

思路：

取长和宽里比较小的一个值，逐层输出，剩余一层再单独判断。

代码：

    int min(int a, int b){
        if(a < b)
            return a;
        return b;
    }
    vector<int> spiralOrder(vector<vector<int> > &matrix) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        vector<int> result;
        result.clear();
        int m = matrix.size();
        if(m == 0)
            return result;
        int n = matrix[0].size();
        if(n == 0)
            return result;
        int i,j;
        for(i = 0; i < min(m,n)/2; i++){
            for(j = i; j < n-1-i; j++)
                result.push_back(matrix[i][j]);
            for(j = i; j < m-1-i; j++)
                result.push_back(matrix[j][n-1-i]);
            for(j = n-1-i; j > i; j--)
                result.push_back(matrix[m-1-i][j]);
            for(j = m-1-i; j > i; j--)
                result.push_back(matrix[j][i]);
        }
        if(min(m,n)%2 == 1){
            if(m < n){
                for(i = m/2; i < n-m/2; i++)
                    result.push_back(matrix[m/2][i]);
            }
            else{
                for(i = n/2; i < m-n/2; i++)
                    result.push_back(matrix[i][n/2]);
            }
        }
        return result;
    }