牛客-剑指0ffer-顺时针打印矩阵

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.

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        int row = matrix.size();
        int col = matrix[0].size();
        vector<int> res;
        
        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;

    }
};