类似蛇形填数的板子

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        vector<int>vt;
        if(matrix.empty()||matrix[0].size()==0)return vt;
        int n=matrix.size(),m=matrix[0].size();
        int book[n+5][m+5];
        memset(book,0,sizeof book);
        int tol=1,x=0,y=0;
        book[0][0]=1;
        vt.push_back(matrix[0][0]);
        while(tol<n*m)
        {
            while(y+1<m&&book[x][y+1]==0)
            {
                vt.push_back(matrix[x][++y]);
                tol++;
                book[x][y]=1;
            }
            while(x+1<n&&book[x+1][y]==0)
            {
                vt.push_back(matrix[++x][y]);
                tol++;
                book[x][y]=1;
            }
            while(y-1>=0&&book[x][y-1]==0)
            {
                vt.push_back(matrix[x][--y]);
                tol++;
                book[x][y]=1;
            }
            while(x-1>=0&&book[x-1][y]==0)
            {
                vt.push_back(matrix[--x][y]);
                tol++;
                book[x][y]=1;
            }
        }
        return vt;
    }
};