面试题29：顺时针打印矩阵

vector<int> printMatrix(vector<vector<int> > matrix) {
        if(matrix.empty())
            cerr<<"wrong input" ;
        int raw_end=matrix.size()-1;
        int col_end=matrix[0].size()-1;
        int raw_start=0;
        int col_start=0;
        vector<int> result;
        while(raw_start<=raw_end&&col_start<=col_end){
            FindMatrix(matrix,raw_start,raw_end,col_start,col_end,result);
            raw_start=raw_start+1;
            raw_end=raw_end-1;
            col_start=col_start+1;
            col_end=col_end-1;
        }
        return result;
    }
    vector<int> FindMatrix(const vector<vector<int> >& matrix,int raw_start,int raw_end,int col_start,int col_end,vector<int>& result){

        for(int j=col_start;j<=col_end;j++)
            result.push_back(matrix[raw_start][j]);
        if(raw_end>raw_start){//从上到下打印一列->至少要两行
            for(int i=raw_start+1;i<=raw_end;i++)
            result.push_back(matrix[i][col_end]);
        }
         if(raw_end>raw_start&&col_end>col_start){//从右向左打印一行->至少要两行两列
             for(int j=col_end-1;j>=col_start;j--)
                 result.push_back(matrix[raw_end][j]);
         }
         if(raw_end>raw_start+1&&col_end>col_start){//从下到上打印一列->至少要三行两列
             for(int i=raw_end-1;i>=raw_start+1;i--)
                 result.push_back(matrix[i][col_start]);
         }
        return result;
    }