C# 从数据表结构计算前序树遍历
我有一个具有以下结构的数据表：C# 从数据表结构计算前序树遍历,c#,modified-preorder-tree-t,C#,Modified Preorder Tree T,我有一个具有以下结构的数据表： Root | Level 1 | Level 2 | Level 3 | Tree L | Tree R Food 1 18 Fruit 2 11 Red 3 6 Cherry
Root | Level 1 | Level 2 | Level 3 | Tree L | Tree R
Food 1 18
Fruit 2 11
Red 3 6
Cherry 4 5
Yellow 7 10
Banana 8 9
Meat 12 17
Beef 13 14
Pork 15 16
有人能建议我如何使用代码来计算左右值吗？因此，您希望跟踪树的访问顺序，但您将顺序分为
LR节点访问节点节点.Visit（）private static List<Tuple<char,Node>> VisitOrder = new List<Tuple<char,Node>>();
public void Visit()
{
VisitOrder.Add(Tuple.Create('L', this));
// whatever visit logic you use here
VisitOrder.Add(Tuple.Create('R', this));
}
以下是我是如何找到答案的：
private class FolderRow
{
public int Indent
{
get { return this.Row.GetValue("Indent", 0); }
set { this.Row["Indent"] = value; }
}
public int Left
{
get { return this.Row.GetValue("Tree L", 0); }
set { this.Row["Tree L"] = value; }
}
public int Right
{
get { return this.Row.GetValue("Tree R", 0); }
set { this.Row["Tree R"] = value; }
}
public Guid Id
{
get { return this.Row.GetValue("FolderID", Guid.Empty); }
}
public DataRow Row { get; private set; }
public int RowNum { get; set; }
public bool RowComplete { get { return this.Left > 0 && this.Right > 0; } }
public FolderRow(DataRow row, int rowNum)
{
this.Row = row;
this.RowNum = rowNum;
}
}
[TestMethod]
public void ImportFolderStructure()
{
var inputTable = FileUtil.GetDataSetFromExcelFile(new FileInfo(@"c:\SampleTree.xlsx")).Tables[0];
var currentLevel = 0;
var nodeCount = 1;
var currentRow = 0;
inputTable.Columns.Add("Indent", typeof (int));
inputTable.Columns.Add("Path", typeof (string));
var rightStack = new List<FolderRow>();
foreach (DataRow row in inputTable.Rows)
row["Indent"] = GetLevelPopulated(row);
foreach (DataRow row in inputTable.Rows)
{
if (row.GetValue("Indent", 0) == 0)
row["Tree L"] = 1;
}
while (true)
{
var row = GetRow(inputTable, currentRow);
if (row.Indent == 0)
{
currentRow++;
rightStack.Add(row);
continue;
}
// if the indent of this row is greater than the previous row ...
if (row.Indent > currentLevel)
{
currentLevel++;
nodeCount++;
row.Left = nodeCount;
// ... check the next row to see if it is further indented
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
} else if (row.Indent == currentLevel)
{
nodeCount++;
row.Left = nodeCount;
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
} else if (row.Indent < currentLevel)
{
currentLevel--;
nodeCount++;
row.Left = nodeCount;
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
}
if (inputTable.Rows.Cast<DataRow>().Select(r => new FolderRow(r, -1)).All(r => r.RowComplete))
break;
}
}
private int HandleNextRow(FolderRow row, int currentRow, List<FolderRow> rightStack, DataTable inputTable, ref int currentLevel,
ref int nodeCount)
{
var nextRow = GetRow(inputTable, currentRow + 1);
if (nextRow != null)
{
if (nextRow.Indent > row.Indent)
{
// ok the current row has a child so we will need to set the tree right of that, add to stack
rightStack.Add(row);
}
else if (nextRow.Indent == row.Indent)
{
nodeCount++;
row.Right = nodeCount;
}
else if (nextRow.Indent < row.Indent)
{
nodeCount++;
row.Right = nodeCount;
nodeCount++;
// here we need to get the most recently added row to rightStack, set the Right to the current nodeCount
var stackLast = rightStack.LastOrDefault();
if (stackLast != null)
{
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
}
currentLevel--;
}
currentRow++;
if (rightStack.Count > 1)
{
// before we move on to the next row, we need to check if there is more than one row still in right stack and
// the new current row's ident is less than the current branch (not current leaf)
var newCurrentRow = GetRow(inputTable, currentRow);
var stackLast = rightStack.LastOrDefault();
if (newCurrentRow.Indent == stackLast.Indent)
{
nodeCount++;
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
}
}
}
else
{
// reached the bottom
nodeCount++;
row.Right = nodeCount;
// loop through the remaining items in rightStack and set their right values
var stackLast = rightStack.LastOrDefault();
while (stackLast != null)
{
nodeCount++;
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
stackLast = rightStack.LastOrDefault();
}
}
return currentRow;
}
private FolderRow GetRow(DataTable inputTable, int rowCount)
{
if (rowCount >= inputTable.Rows.Count)
return null;
return rowCount < 0 ? null : new FolderRow(inputTable.Rows[rowCount],rowCount);
}
private int GetLevelPopulated(DataRow row)
{
var level = 0;
while (level < 14)
{
if (level == 0 && row["Root"] != DBNull.Value)
return level;
level++;
if (row["Level " + level] != DBNull.Value)
return level;
}
return -1;
}
私有类文件夹行
{
公共整数缩进
{
get{返回this.Row.GetValue（“缩进”，0）；}
设置{this.Row[“Indent”]=value；}
}
公共整数左
{
get{返回this.Row.GetValue（“树L”，0）；}
设置{this.Row[“Tree L”]=value；}
}
公权
{
get{返回this.Row.GetValue（“树R”，0）；}
设置{this.Row[“Tree R”]=value；}
}
公共Guid Id
{
get{返回this.Row.GetValue（“FolderID”，Guid.Empty）；}
}
公共数据行{get；private set；}
public int RowNum{get；set；}
公共bool行完成{get{返回this.Left>0&&this.Right>0；}
公共文件夹行（DataRow行，int rowNum）
{
this.Row=行；
this.RowNum=RowNum；
}
}
[测试方法]
public void ImportFolderStructure（）
{
var inputable=FileUtil.GetDataSetFromExcelFile（新文件信息（@“c:\SampleTree.xlsx”））。表[0]；
var currentLevel=0；
var nodeCount=1；
var currentRow=0；
可输入.Columns.Add（“缩进”，typeof（int））；
可输入.Columns.Add（“路径”，类型（字符串））；
var rightStack=新列表（）；
foreach（可输入的.Rows中的数据行）
行[“缩进”]=GetLevelPopulated（行）；
foreach（可输入的.Rows中的数据行）
{
if（row.GetValue（“缩进”，0）==0）
行[“树L”]=1；
}
while（true）
{
var row=GetRow（可输入，currentRow）；
if（row.Indent==0）
{
currentRow++；
添加（行）；
持续
}
//如果此行的缩进大于上一行。。。
如果（行缩进>当前级别）
{
currentLevel++；
nodeCount++；
行左=节点计数；
//…检查下一行是否进一步缩进
currentRow=HandleNextRow（行、currentRow、rightStack、可输入、参考currentLevel、参考nodeCount）；
}else if（row.Indent==currentLevel）
{
nodeCount++；
行左=节点计数；
currentRow=HandleNextRow（行、currentRow、rightStack、可输入、参考currentLevel、参考nodeCount）；
}else if（行缩进<当前级别）
{
当前级别--；
nodeCount++；
行左=节点计数；
currentRow=HandleNextRow（行、currentRow、rightStack、可输入、参考currentLevel、参考nodeCount）；
}
if（inputable.Rows.Cast（）.Select（r=>newfolderrow（r，-1））.All（r=>r.RowComplete））
打破
}
}
私有int HandleNextRow（FolderRow行、int currentRow行、List rightStack、DataTable可输入、ref int currentLevel、，
ref int节点计数）
{
var nextRow=GetRow（可输入，currentRow+1）；
如果（nextRow！=null）
{
如果（下一行缩进>行缩进）
{
//好的，当前行有一个子行，所以我们需要将树设置在它的右边，添加到堆栈
添加（行）；
}
else if（nextRow.Indent==行.Indent）
{
nodeCount++；
row.Right=节点计数；
}
否则如果（下一行缩进<行缩进）
{
nodeCount++；
row.Right=节点计数；
nodeCount++；
//在这里，我们需要获取最近添加到rightStack的行，将其设置为当前nodeCount
var stackLast=rightStack.LastOrDefault（）；
if（stackLast！=null）
{
stackLast.Right=nodeCount；
rightStack.Remove（stackLast）；
}
当前级别--；
}
currentRow++；
如果（rightStack.Count>1）
{
//在继续下一行之前，我们需要检查是否有多行仍然在右堆栈中，并且
//新的当前行的标识小于当前分支（不是当前叶）
var newCurrentRow=GetRow（可输入，currentRow）；
var stackLast=rightStack.LastOrDefault（）；
if（newCurrentRow.Indent==stackLast.Indent）
{
nodeCount++；
stackLast.Right=nodeCount；
rightStack.Remove（stackLast）；
}
}
}
其他的
{
//跌入谷底
nodeCount++；
row.Right=节点计数；
//循环查看rightStack中的其余项并设置其正确的值
var stackLast=rightStack.LastOrDefault（）；
while（stackLast！=null）
{
nodeCount++；
stackLast.Right=nodeCount；
rightStack.Remove（stackLast）；
stackLast=rightStack.LastOrDefault（）；
}
}
返回当前行；
}
私有FolderRow GetRow（数据表可输入，整数行计数）
{
if（rowCount>=inputable.Rows.Count）
返回null；
返回rowCount<0？空：新建FolderRow（可输入。Rows[rowCount]，rowCount）；
}
私有int GetLevelPop
private class FolderRow
{
public int Indent
{
get { return this.Row.GetValue("Indent", 0); }
set { this.Row["Indent"] = value; }
}
public int Left
{
get { return this.Row.GetValue("Tree L", 0); }
set { this.Row["Tree L"] = value; }
}
public int Right
{
get { return this.Row.GetValue("Tree R", 0); }
set { this.Row["Tree R"] = value; }
}
public Guid Id
{
get { return this.Row.GetValue("FolderID", Guid.Empty); }
}
public DataRow Row { get; private set; }
public int RowNum { get; set; }
public bool RowComplete { get { return this.Left > 0 && this.Right > 0; } }
public FolderRow(DataRow row, int rowNum)
{
this.Row = row;
this.RowNum = rowNum;
}
}
[TestMethod]
public void ImportFolderStructure()
{
var inputTable = FileUtil.GetDataSetFromExcelFile(new FileInfo(@"c:\SampleTree.xlsx")).Tables[0];
var currentLevel = 0;
var nodeCount = 1;
var currentRow = 0;
inputTable.Columns.Add("Indent", typeof (int));
inputTable.Columns.Add("Path", typeof (string));
var rightStack = new List<FolderRow>();
foreach (DataRow row in inputTable.Rows)
row["Indent"] = GetLevelPopulated(row);
foreach (DataRow row in inputTable.Rows)
{
if (row.GetValue("Indent", 0) == 0)
row["Tree L"] = 1;
}
while (true)
{
var row = GetRow(inputTable, currentRow);
if (row.Indent == 0)
{
currentRow++;
rightStack.Add(row);
continue;
}
// if the indent of this row is greater than the previous row ...
if (row.Indent > currentLevel)
{
currentLevel++;
nodeCount++;
row.Left = nodeCount;
// ... check the next row to see if it is further indented
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
} else if (row.Indent == currentLevel)
{
nodeCount++;
row.Left = nodeCount;
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
} else if (row.Indent < currentLevel)
{
currentLevel--;
nodeCount++;
row.Left = nodeCount;
currentRow = HandleNextRow(row, currentRow, rightStack, inputTable, ref currentLevel, ref nodeCount);
}
if (inputTable.Rows.Cast<DataRow>().Select(r => new FolderRow(r, -1)).All(r => r.RowComplete))
break;
}
}
private int HandleNextRow(FolderRow row, int currentRow, List<FolderRow> rightStack, DataTable inputTable, ref int currentLevel,
ref int nodeCount)
{
var nextRow = GetRow(inputTable, currentRow + 1);
if (nextRow != null)
{
if (nextRow.Indent > row.Indent)
{
// ok the current row has a child so we will need to set the tree right of that, add to stack
rightStack.Add(row);
}
else if (nextRow.Indent == row.Indent)
{
nodeCount++;
row.Right = nodeCount;
}
else if (nextRow.Indent < row.Indent)
{
nodeCount++;
row.Right = nodeCount;
nodeCount++;
// here we need to get the most recently added row to rightStack, set the Right to the current nodeCount
var stackLast = rightStack.LastOrDefault();
if (stackLast != null)
{
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
}
currentLevel--;
}
currentRow++;
if (rightStack.Count > 1)
{
// before we move on to the next row, we need to check if there is more than one row still in right stack and
// the new current row's ident is less than the current branch (not current leaf)
var newCurrentRow = GetRow(inputTable, currentRow);
var stackLast = rightStack.LastOrDefault();
if (newCurrentRow.Indent == stackLast.Indent)
{
nodeCount++;
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
}
}
}
else
{
// reached the bottom
nodeCount++;
row.Right = nodeCount;
// loop through the remaining items in rightStack and set their right values
var stackLast = rightStack.LastOrDefault();
while (stackLast != null)
{
nodeCount++;
stackLast.Right = nodeCount;
rightStack.Remove(stackLast);
stackLast = rightStack.LastOrDefault();
}
}
return currentRow;
}
private FolderRow GetRow(DataTable inputTable, int rowCount)
{
if (rowCount >= inputTable.Rows.Count)
return null;
return rowCount < 0 ? null : new FolderRow(inputTable.Rows[rowCount],rowCount);
}
private int GetLevelPopulated(DataRow row)
{
var level = 0;
while (level < 14)
{
if (level == 0 && row["Root"] != DBNull.Value)
return level;
level++;
if (row["Level " + level] != DBNull.Value)
return level;
}
return -1;
}