剑指 Offer 29. 顺时针打印矩阵

思路#

模拟。思路来自：https://leetcode-cn.com/problems/shun-shi-zhen-da-yin-ju-zhen-lcof/solution/mian-shi-ti-29-shun-shi-zhen-da-yin-ju-zhen-she-di/

 

代码实现#

class Solution {
private:
    vector<int> res;
    int n, m;
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        //n行m列
        n = matrix.size();
        if(n == 0) return res;
        m = matrix[0].size();
        if(m == 0) return res;
        
        int i = 0, j = 0;
        int r = m-1, b = n-1, l = 0, t = 0;

        while(1) {
            for(int i = l; i <= r; ++i)
                res.push_back(matrix[t][i]);
            if(++t > b)
                break;

            for(int i = t; i <= b; ++i)
                res.push_back(matrix[i][r]);
            if(--r < l)
                break;
            
            for(int i = r; i >= l; --i)
                res.push_back(matrix[b][i]);
            if(--b < t)
                break;

            for(int i = b; i >= t; --i)
                res.push_back(matrix[i][l]);
            if(++l > r)
                break;
        }

        return res;
    }
};

 

复杂度分析#