顺时针打印矩阵 C++解法

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 printMatrix(vector> matrix)
        {
            int row = matrix.size();
            int col = matrix[0].size();
            vector 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;
        }
    };

思路：用左上和右下的坐标定位出一次要旋转打印的数据，一次旋转打印结束后，往对角分别前进和后退一个单位。通过对top与bottom，left与right的比较来限定for循环范围。