// Time Complexity: O(N)
// Space Complexity: O(1)
public ListNode GetIntersection(ListNode headA, ListNode headB)
{
if (runnerA == null || runnerB == null)
{
return(null);
}
ListNode runnerA = headA;
listNode runnerB = headB;
int lengthA = 0;
int lengthB = 0;
while (runnerA != null)
{
++lengthA;
runnerA = runnerA.next;
}
while (runnerB != null)
{
++lengthB;
runnerB = runnerB.next;
}
runnerA = headA;
runnerB = headB;
int diff = lengthA - lengthB;
while (diff > 0)
{
runnerA = runnerA.next;
--diff;
}
while (diff < 0)
{
runnerB = runnerB.next;
++diff;
}
while (runnerA.next != null && runnerB.next != null)
{
if (runnerA = runnerB)
{
return(runnerA);
}
runnerA = runnerA.next;
runnerB = runnerB.next;
}
return(null);
}
public node ReadFromStream(Stream stream)
{
var dt = (DataType)stream.ReadByte();
var ts = dt & DataType.TypeSpecMask;
dt &= DataType.Mask;
var hasRefId = false;
var ix = Array.IndexOf(_withRefs, dt);
if (ix >= 0)
{
hasRefId = true;
dt = _reffables[ix];
}
node node;
DataType keyType = 0;
switch (dt)
{
case DataType.End: return(null);
case DataType.Byte: node = new valueNode {
Value = (byte)stream.ReadByte()
}; break;
case DataType.SByte: node = new valueNode {
Value = (sbyte)(byte)stream.ReadByte()
}; break;
case DataType.Int16: node = new valueNode {
Value = BitConverter.ToInt16(stream.Read(2), 0)
}; break;
case DataType.UInt16: node = new valueNode {
Value = BitConverter.ToUInt16(stream.Read(2), 0)
}; break;
case DataType.Int32: node = new valueNode {
Value = BitConverter.ToInt32(stream.Read(4), 0)
}; break;
case DataType.UInt32: node = new valueNode {
Value = BitConverter.ToUInt32(stream.Read(4), 0)
}; break;
case DataType.Single: node = new valueNode {
Value = BitConverter.ToSingle(stream.Read(4), 0)
}; break;
case DataType.Int64: node = new valueNode {
Value = BitConverter.ToInt64(stream.Read(8), 0)
}; break;
case DataType.UInt64: node = new valueNode {
Value = BitConverter.ToUInt64(stream.Read(8), 0)
}; break;
case DataType.Double: node = new valueNode {
Value = BitConverter.ToDouble(stream.Read(8), 0)
}; break;
case DataType.DateTime: node = new valueNode {
Value = DateTime.FromBinary(BitConverter.ToInt64(stream.Read(8), 0))
}; break;
case DataType.Decimal: node = new valueNode {
Value = stream.ReadDecimalOptim()
}; break;
case DataType.String: node = new valueNode {
Value = readBuffer(stream, true).FromUtf8()
}; break;
case DataType.RawData: node = new valueNode {
Value = readBuffer(stream, false)
}; break;
case DataType.Null: node = new valueNode {
Value = null
}; break;
case DataType.False: node = new valueNode {
Value = false
}; break;
case DataType.True: node = new valueNode {
Value = true
}; break;
case DataType.Ref: node = new valueNode {
Value = stream.ReadInt32Optim()
}; break;
case DataType.KeyValuePair: node = new kvpNode {
Key = ReadFromStream(stream), Value = ReadFromStream(stream)
}; break;
case DataType.List:
var list = new List <node>();
while ((node = ReadFromStream(stream)) != null)
{
list.Add(node);
}
node = new listNode {
List = list
};
break;
case DataType.DictionaryOther:
keyType = (DataType)stream.ReadByte();
goto case DataType.DictionaryInt64;
case DataType.DictionaryInt64:
case DataType.DictionaryString:
case DataType.DictionaryTwoStrings:
var dict = new Dictionary <object, node>();
// Dictionaries encode value first, then key.
while ((node = ReadFromStream(stream)) != null)
{
object key;
switch (dt)
{
case DataType.DictionaryInt64:
key = stream.ReadInt64Optim();
break;
case DataType.DictionaryString:
key = readBuffer(stream, true).FromUtf8();
break;
case DataType.DictionaryTwoStrings:
var fieldName = readBuffer(stream, true).FromUtf8();
var declaringType = readBuffer(stream, true).FromUtf8();
key = declaringType.Length > 0 ? new FieldNameWithType(fieldName, declaringType) : (object)fieldName;
break;
case DataType.DictionaryOther:
switch (keyType)
{
case DataType.UInt64:
key = stream.ReadUInt64Optim();
break;
case DataType.Single:
key = BitConverter.ToSingle(stream.Read(4), 0);
break;
case DataType.Double:
key = BitConverter.ToSingle(stream.Read(8), 0);
break;
case DataType.DateTime:
key = DateTime.FromBinary(BitConverter.ToInt64(stream.Read(8), 0));
break;
case DataType.Decimal:
key = stream.ReadDecimalOptim();
break;
case DataType.RawData:
key = readBuffer(stream, false).FromUtf16();
break;
default:
throw new InvalidOperationException("Invalid dictionary key type.");
}
break;
default:
throw new InvalidOperationException("This case should never be reached.");
}
dict[key] = node;
}
node = new dictNode {
Dictionary = dict, KeyType = keyType
};
break;
default:
throw new InvalidOperationException("Invalid object type in binary format.");
}
node.DataType = dt;
if (ts == DataType.SimpleTypeSpec || (node.TypeSpecIsFull = (ts == DataType.FullTypeSpec)))
{
node.TypeSpec = readBuffer(stream, true).FromUtf8();
}
if (hasRefId)
{
node.RefId = stream.ReadInt32Optim();
}
return(node);
}
