题目描述

输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，例如，如果输入如下4 X 4矩阵：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

则依次打印出数字

1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.

解决方法

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        vector<int> res;
        int row = matrix.size();
        int col = matrix[0].size();
        
        if(row == 0 || col==0) return res;
        
        int left = 0, top = 0,right = col-1,bottom=row-1;
        while(left <= right && top<= bottom)
        {
            for(int i=left;i<=right;++i) 
                res.push_back(matrix[top][i]);
            for(int i=top+1;i<=bottom;++i) 
                res.push_back(matrix[i][right]);
            if(top != bottom)
                for(int i=right-1;i>=left;--i) 
                    res.push_back(matrix[bottom][i]);
            if(left != right)
                for(int i= bottom-1;i>top;--i)
                    res.push_back(matrix[i][left]);
            left++,top++,right--,bottom--;
        }
        return res;
        
    }
};