Spiral matrix - mock interview - good performance, but less flexible to think about alternative idea.

SpiralMatrix_mockInterview.java

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--;
    }
  }
  //.... stop here. The code is perfect, bug free, very clean.
}