diff --git a/pkg/vm/memory/memory.go b/pkg/vm/memory/memory.go
index fba6a050..ea7485a9 100644
--- a/pkg/vm/memory/memory.go
+++ b/pkg/vm/memory/memory.go
@@ -6,17 +6,17 @@ import (
 
 // Memory represents the Cairo VM's memory.
 type Memory struct {
-	data [][]MaybeRelocatable
+	data         map[Relocatable]MaybeRelocatable
+	num_segments uint
 }
 
-func NewMemory(data [][]MaybeRelocatable) *Memory {
-	return &Memory{data}
+func NewMemory() *Memory {
+	data := make(map[Relocatable]MaybeRelocatable)
+	return &Memory{data, 0}
 }
 
 // Inserts a value in some memory address, given by a Relocatable value.
-func (m *Memory) Insert(addr *Relocatable, val *MaybeRelocatable) error {
-	addr_idx, addr_offset := addr.into_indexes()
-
+func (m *Memory) Insert(addr Relocatable, val *MaybeRelocatable) error {
 	// FIXME: There should be a special handling if the key
 	// segment index is negative. This is an edge
 	// case, so for now let's raise an error.
@@ -24,40 +24,24 @@ func (m *Memory) Insert(addr *Relocatable, val *MaybeRelocatable) error {
 		return errors.New("Segment index of key is negative - unimplemented")
 	}
 
-	segment := &m.data[addr_idx]
-	segment_len := len(*segment)
-
-	// When the offset of the insertion address is greater than the max
-	// offset of the segment, memory cells are filled with `nil` in the
-	// intermediate values, if any. So if segment has length 2 (last idx is 1)
-	// and we want to insert something at index 4, index 2 and 3 will be filled
-	// with `nil`, and index 4 will have the desired value.
-	if segment_len <= int(addr_offset) {
-		new_segment_len := addr_offset + 1
-		for i := segment_len; i < int(new_segment_len); i++ {
-			*segment = append(*segment, MaybeRelocatable{nil})
-		}
+	// Check that insertions are preformed within the memory bounds
+	if addr.segmentIndex >= int(m.num_segments) {
+		return errors.New("Error: Inserting into a non allocated segment")
 	}
 
-	// At this point, something exists at the `addr_offset` for sure.
-	// Check that the value at that offset is `nil` and if it is, then
-	// swap that `nil` with the desired value.
-	if (*segment)[addr_offset].is_nil() {
-		(*segment)[addr_offset] = *val
-		// If there wasn't `nil`, then we are trying to overwrite in that
-		// address. If the value we are trying to insert is not the same as
-		// the one that was already in that location, raise an error.
-	} else if (*segment)[addr_offset] != *val {
+	// Check for possible overwrites
+	prev_elem, ok := m.data[addr]
+	if ok && prev_elem != *val {
 		return errors.New("Memory is write-once, cannot overwrite memory value")
 	}
 
+	m.data[addr] = *val
+
 	return nil
 }
 
 // Gets some value stored in the memory address `addr`.
-func (m *Memory) Get(addr *Relocatable) (*MaybeRelocatable, error) {
-	addr_idx, addr_offset := addr.into_indexes()
-
+func (m *Memory) Get(addr Relocatable) (*MaybeRelocatable, error) {
 	// FIXME: There should be a special handling if the key
 	// segment index is negative. This is an edge
 	// case, so for now let's raise an error.
@@ -70,7 +54,11 @@ func (m *Memory) Get(addr *Relocatable) (*MaybeRelocatable, error) {
 	// check if the value is a `Relocatable` with a negative
 	// segment index. Again, these are edge cases so not important
 	// right now. See cairo-vm code for details.
-	value := m.data[addr_idx][addr_offset]
+	value, ok := m.data[addr]
+
+	if !ok {
+		return nil, errors.New("Memory Get: Value not found")
+	}
 
 	return &value, nil
 }
diff --git a/pkg/vm/memory/memory_test.go b/pkg/vm/memory/memory_test.go
index 96eadd71..15a94edd 100644
--- a/pkg/vm/memory/memory_test.go
+++ b/pkg/vm/memory/memory_test.go
@@ -8,9 +8,10 @@ import (
 )
 
 func TestMemoryInsert(t *testing.T) {
-	// Instantiate memory with 3 empty segments
-	data := make([][]memory.MaybeRelocatable, 3)
-	mem := memory.NewMemory(data)
+	mem_manager := memory.NewMemorySegmentManager()
+	mem_manager.AddSegment()
+	mem_manager.AddSegment()
+	mem := &mem_manager.Memory
 
 	// Instantiate the address where we want to insert and the value.
 	// We will insert the value Int(5) in segment 1, offset 0
@@ -36,9 +37,10 @@ func TestMemoryInsert(t *testing.T) {
 }
 
 func TestMemoryInsertWithHoles(t *testing.T) {
-	// Instantiate memory with 3 empty segments
-	data := make([][]memory.MaybeRelocatable, 3)
-	mem := memory.NewMemory(data)
+	mem_manager := memory.NewMemorySegmentManager()
+	mem_manager.AddSegment()
+	mem_manager.AddSegment()
+	mem := &mem_manager.Memory
 
 	// Instantiate the address where we want to insert and the value.
 	// We will insert the MaybeRelocatable Int(7) in segment 1, offset 2
@@ -61,25 +63,155 @@ func TestMemoryInsertWithHoles(t *testing.T) {
 	if !reflect.DeepEqual(res_val, val) {
 		t.Errorf("Inserted value and original value are not the same")
 	}
+}
+
+func TestMemoryInsertOverWriteSameValue(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+	mem := &mem_manager.Memory
 
-	// Since we inserted in segment 1, offset 2 in an empty memory, now
-	// the values in segment 1, offset 0 and 1 should be `nil` (memory holes)
-	hole1_addr := memory.NewRelocatable(1, 0)
-	hole2_addr := memory.NewRelocatable(1, 1)
+	// We will insert the MaybeRelocatable Int(7) in segment 0, offset 0
+	key := mem_manager.AddSegment()
+	val := memory.NewMaybeRelocatableInt(7)
 
-	hole1, err := mem.Get(hole1_addr)
+	// Make the insertion
+	err := mem.Insert(key, val)
+	if err != nil {
+		t.Errorf("Insert error in test: %s", err)
+	}
+
+	// Insert the same value again and check it doesn't fail
+	err2 := mem.Insert(key, val)
+	if err2 != nil {
+		t.Errorf("Insert error in test: %s", err)
+	}
+}
+
+func TestMemoryInsertOverWriteValue(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+	mem := &mem_manager.Memory
+
+	// We will insert the MaybeRelocatable Int(7) in segment 0, offset 0
+	key := mem_manager.AddSegment()
+	val := memory.NewMaybeRelocatableInt(7)
+
+	// Make the insertion
+	err := mem.Insert(key, val)
+	if err != nil {
+		t.Errorf("Insert error in test: %s", err)
+	}
+
+	// Insert another value into the same address and check that it fails
+	val2 := memory.NewMaybeRelocatableInt(8)
+	err2 := mem.Insert(key, val2)
+	if err2 == nil {
+		t.Errorf("Overwritting memory value should fail")
+	}
+}
+
+func TestMemoryInsertUnallocatedSegment(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+	mem := &mem_manager.Memory
+
+	// Instantiate the address where we want to insert and the value.
+	// We will insert the value Int(5) in segment 1, offset 0
+	key := memory.NewRelocatable(1, 0)
+	val := memory.NewMaybeRelocatableInt(5)
+
+	// Make the insertion
+	err := mem.Insert(key, val)
+	if err == nil {
+		t.Errorf("Insertion on unallocated segment should fail")
+	}
+}
+
+func TestMemorySegmentsLoadDataUnallocatedSegment(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+
+	ptr := memory.NewRelocatable(1, 0)
+	data := []memory.MaybeRelocatable{*memory.NewMaybeRelocatableInt(5)}
+
+	// Load Data
+	_, err := mem_manager.LoadData(ptr, &data)
+	if err == nil {
+		t.Errorf("Insertion on unallocated segment should fail")
+	}
+}
+
+func TestMemorySegmentsLoadDataOneElement(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+	mem_manager.AddSegment()
+
+	ptr := memory.NewRelocatable(0, 0)
+	val := memory.NewMaybeRelocatableInt(5)
+	data := []memory.MaybeRelocatable{*val}
+
+	// Load Data
+	end_ptr, err := mem_manager.LoadData(ptr, &data)
+	if err != nil {
+		t.Errorf("LoadData error in test: %s", err)
+	}
+
+	// Check returned ptr
+	expected_end_ptr := memory.NewRelocatable(0, 1)
+	if !reflect.DeepEqual(end_ptr, expected_end_ptr) {
+		t.Errorf("LoadData returned wrong ptr")
+	}
+
+	// Check inserted value
+	res_val, err := mem_manager.Memory.Get(ptr)
 	if err != nil {
 		t.Errorf("Get error in test: %s", err)
 	}
 
-	hole2, err := mem.Get(hole2_addr)
+	// Check that the original and the retrieved values are the same
+	if !reflect.DeepEqual(res_val, val) {
+		t.Errorf("Inserted value and original value are not the same")
+	}
+}
+
+func TestMemorySegmentsLoadDataTwoElements(t *testing.T) {
+	mem_manager := memory.NewMemorySegmentManager()
+	mem_manager.AddSegment()
+
+	ptr := memory.NewRelocatable(0, 0)
+	val := memory.NewMaybeRelocatableInt(5)
+	val2 := memory.NewMaybeRelocatableInt(5)
+	data := []memory.MaybeRelocatable{*val, *val2}
+
+	// Load Data
+	end_ptr, err := mem_manager.LoadData(ptr, &data)
+	if err != nil {
+		t.Errorf("LoadData error in test: %s", err)
+	}
+
+	// Check returned ptr
+	expected_end_ptr := memory.NewRelocatable(0, 2)
+	if !reflect.DeepEqual(end_ptr, expected_end_ptr) {
+		t.Errorf("LoadData returned wrong ptr")
+	}
+
+	// Check inserted values
+
+	// val
+	res_val, err := mem_manager.Memory.Get(ptr)
+	if err != nil {
+		t.Errorf("Get error in test: %s", err)
+	}
+
+	// Check that the original and the retrieved values are the same
+	if !reflect.DeepEqual(res_val, val) {
+		t.Errorf("Inserted value and original value are not the same")
+	}
+
+	//val2
+	ptr2 := memory.NewRelocatable(0, 1)
+	res_val2, err := mem_manager.Memory.Get(ptr2)
 	if err != nil {
 		t.Errorf("Get error in test: %s", err)
 	}
 
-	// Check that we got the holes from memory
-	expected_hole := memory.NewMaybeRelocatableNil()
-	if !reflect.DeepEqual(hole1, expected_hole) || !reflect.DeepEqual(hole2, expected_hole) {
-		t.Errorf("Expected nil value but got another")
+	// Check that the original and the retrieved values are the same
+	if !reflect.DeepEqual(res_val2, val2) {
+		t.Errorf("Inserted value and original value are not the same")
 	}
 }
diff --git a/pkg/vm/memory/relocatable.go b/pkg/vm/memory/relocatable.go
index 8a6654a1..19d1c8ab 100644
--- a/pkg/vm/memory/relocatable.go
+++ b/pkg/vm/memory/relocatable.go
@@ -11,19 +11,8 @@ type Relocatable struct {
 
 // Creates a new Relocatable struct with the specified segment index
 // and offset.
-func NewRelocatable(segment_idx int, offset uint) *Relocatable {
-	return &Relocatable{segment_idx, offset}
-}
-
-// Get the the indexes of the Relocatable struct.
-// Returns a tuple with both values (segment_index, offset)
-func (r *Relocatable) into_indexes() (uint, uint) {
-	if r.segmentIndex < 0 {
-		corrected_segment_idx := uint(-(r.segmentIndex + 1))
-		return corrected_segment_idx, r.offset
-	}
-
-	return uint(r.segmentIndex), r.offset
+func NewRelocatable(segment_idx int, offset uint) Relocatable {
+	return Relocatable{segment_idx, offset}
 }
 
 // Int in the Cairo VM represents a value in memory that
@@ -47,12 +36,14 @@ func NewMaybeRelocatableInt(felt uint) *MaybeRelocatable {
 	return &MaybeRelocatable{inner: Int{felt}}
 }
 
-// Creates a new MaybeRelocatable with a `nil` inner value
-func NewMaybeRelocatableNil() *MaybeRelocatable {
-	return &MaybeRelocatable{inner: nil}
+// If m is Int, returns the inner value + true, if not, returns zero + false
+func (m *MaybeRelocatable) GetInt() (Int, bool) {
+	int, is_type := m.inner.(Int)
+	return int, is_type
 }
 
-// Checks if inner value of MaybeRelocatable is `nil`
-func (m *MaybeRelocatable) is_nil() bool {
-	return m.inner == nil
+// If m is Relocatable, returns the inner value + true, if not, returns zero + false
+func (m *MaybeRelocatable) GetRelocatable() (Relocatable, bool) {
+	rel, is_type := m.inner.(Relocatable)
+	return rel, is_type
 }
diff --git a/pkg/vm/memory/segments.go b/pkg/vm/memory/segments.go
index 3fc1c025..d9b4f4d6 100644
--- a/pkg/vm/memory/segments.go
+++ b/pkg/vm/memory/segments.go
@@ -5,5 +5,30 @@ package memory
 // the memory at the end of the VM run.
 type MemorySegmentManager struct {
 	segmentSizes map[uint]uint
-	memory       Memory
+	Memory       Memory
+}
+
+func NewMemorySegmentManager() *MemorySegmentManager {
+	memory := NewMemory()
+	return &MemorySegmentManager{make(map[uint]uint), *memory}
+}
+
+// Adds a memory segment and returns the first address of the new segment
+func (m *MemorySegmentManager) AddSegment() Relocatable {
+	ptr := Relocatable{int(m.Memory.num_segments), 0}
+	m.Memory.num_segments += 1
+	return ptr
+}
+
+// Writes data into the memory from address ptr and returns the first address after the data.
+// If any insertion fails, returns (0,0) and the memory insertion error
+func (m *MemorySegmentManager) LoadData(ptr Relocatable, data *[]MaybeRelocatable) (Relocatable, error) {
+	for _, val := range *data {
+		err := m.Memory.Insert(ptr, &val)
+		if err != nil {
+			return Relocatable{0, 0}, err
+		}
+		ptr.offset += 1
+	}
+	return ptr, nil
 }
diff --git a/pkg/vm/run_context.go b/pkg/vm/run_context.go
index 769e25e1..6ec0deaf 100644
--- a/pkg/vm/run_context.go
+++ b/pkg/vm/run_context.go
@@ -5,7 +5,7 @@ import "github.com/lambdaclass/cairo-vm.go/pkg/vm/memory"
 // RunContext containts the register states of the
 // Cairo VM.
 type RunContext struct {
-	pc memory.Relocatable
-	ap uint
-	fp uint
+	Pc memory.Relocatable
+	Ap memory.Relocatable
+	Fp memory.Relocatable
 }