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.

 

主要是对边界的处理问题。

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        int x = matrix.size();
        int y = matrix[0].size();
        int left = 0, top = 0, right = y - 1, bottom = x - 1;
        vector<int> res;
        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++, right--, top++, bottom--;
        }
        return res;
    }
};