Leetcode 54: spiral matrix - Febuary 5,2018 mock interview as an interviewer

Leetcode54_SpiralMatrix_February5_2018.java

import java.io.*;
import java.util.*;

/*
 * To execute Java, please define "static void main" on a class
 * named Solution.
 *
 * If you need more classes, simply define them inline.
 */

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order. 
For example, Given the following matrix: 
[
  [ 1, 2, 3 ],
  [ 4, 5, 6 ],
  [ 7, 8, 9 ]
]
You should return [1,2,3,6,9,8,7,4,5].
  
  dr = new int[]{0, 1, 0, -1}
  dc = new int[]{1, 0, -1, 0}



class Solution {
  public static void main(String[] args) {

  }
  
  int[] printMatrix(int[][] m) {
    int nRows = m.length;
    if (nRows < 1) return new int[0];
    int nCols = m[0].length;
    int[] result = new int[nRows * nCols];
    int iRowBegin = 0;
    int iColBegin = 0;
    int iRowEnd = nRows - 1;
    int iColEnd = nCols - 1;
    int iR = 0;
    while (true) { // whole one circle
      for (int i = iColBegin; i<= iColEnd; i++) {
        result[iR++] = m[iRowBegin][i];
      }
      iRowBegin++;
      for (int i = iRowBegin; i <= iRowEnd; i++) {
        result[iR++] = m[i][iColEnd];
      }
      iColEnd--;
    }
  }
  
}