题解 | #顺时针打印矩阵#

#include <cstring>
#include <vector>
class Solution {
public:

    int idx=0;
    int dx[4] = {0, 1, 0, -1};
    int dy[4] = {1, 0, -1, 0};

    void changeDir(){
        idx=(idx+1)%4;        
    }
    int used[110][110];
    vector<int> printMatrix(vector<vector<int> > matrix) {
        memset(used, 0, sizeof used);
        int i=0,j=0;
        vector<int> res;
        while(res.size() < matrix[0].size() * matrix.size()){
            if(i<0 || i>=matrix.size() || j<0 || j>=matrix[0].size() || used[i][j]){
                i = i - dx[idx];
                j = j - dy[idx];
                changeDir();
            }else{
                res.push_back(matrix[i][j]);
                used[i][j] = 1;
            }

            i = i + dx[idx];
            j = j + dy[idx]; 
        }
        return res;
    }
};