code: function transpose(matrix) {
  	// For NxN matrix
  	var n = matrix[0].length;
  	var temp;
  
  	// Walk through columns
  	for (var i = 0, j = 0; i < n; i++) {
  		j = i;
  		// Walk through rows
  		while (j < n) {
  			if (i !== j) {
  				temp = matrix[i][j];
  				matrix[i][j] = matrix[j][i];
  				matrix[j][i] = temp;
  			}
  			j++;
  		}
  	}
  }
docs: Transpose a 2D matrix