def __TSORT(self, v: int, S: Stack):
"""(连通域)基于DFS的拓扑排序算法"""
assert (0 <= v) and (v < self.n)
V = self.V[v]
self.clock += 1
V.dTime = self.clock
V.status = VStatus.DISCOVERD
u = self.firstNbr(v)
while -1 < u:
U = self.V[u]
E = self.E[v][u]
if VStatus.UNDISCOVERD == U.status:
U.parent = v
E.type = EType.TREE
print(U, end='\t')
if not self.__TSORT(u, S): # 从顶点u出发深入搜索
return False # 若u及其后代不能拓扑排序(则全图亦必如此),故返回并报告
elif VStatus.DISCOVERD == U.status: # 一旦发现后向边(非DAG),则不必深入,故返回报告
E.type = EType.BACKWARD
return False
else:
E.type = EType.FORWARD if V.dTime > U.dTime else EType.CROSS
u = self.nextNbr(v, u)
V.status = VStatus.VISITED
S.push(self.vertex(v))
return True # v及后代可以拓扑排序
def visitAlongLeftBranch(self, s: Stack):
"""从当前节点出发,沿左分支不断深入,直至没有左分支的节点;沿途节点遇到后立即访问"""
x = copy(self)
while x:
print(x.data, end="->")
if x._rc:
s.push(x._rc)
x = x._lc
def travPre_I2(self):
"""二叉树先序遍历迭代版本"""
s = Stack([])
x = copy(self)
while True:
x.visitAlongLeftBranch(s)
if s.empty():
break
x = s.pop()
def travIn_I1(self):
"""二叉树中序遍历迭代版本1"""
x = copy(self)
s = Stack([])
while True:
if x:
x.goAlongLeftBranch(s)
if s.empty():
break
x = s.pop()
print(x.data, end="->")
x = x.rc
def gotoHLVEL(self, s: Stack):
x = s.top()
while x:
if BinNode.HasLChild(x):
if BinNode.HasRChild(x):
s.push(x.rc)
s.push(x.lc)
else:
s.push(x.rc)
s.pop()
def bcc(self, s: Any):
"""基于DFS的双连通分量分解算法"""
assert (0 <= s) and (s < self.n)
self.__reset()
self.clock = 0
v = s
S = Stack([], self.n)
while True:
if VStatus.UNDISCOVERD == self.status(v):
self.__BCC(v, S)
S.pop()
v += 1
v %= self.n
if s == v:
break
def tSort(self, s: int):
"""基于DFS的拓扑排序算法:
每一个顶点都不会通过边,指向其在此序列中的前驱顶点,这样的一个线性序列,称作原有向图的一个拓扑排序
"""
assert (0 <= s) and (s < self.n)
self.__reset()
self.clock = 0
v = s
S = Stack([], self.n) # 用栈记录排序顶点
while True:
if VStatus.UNDISCOVERD == self.status(v):
if not self.__TSORT(v, S):
while not S.empty(): # 任一连通域(亦即整图)非DAG
S.pop()
break # 则 不必继续计算,故直接返回
v += 1
v %= self.n
if s == v:
break
def __BCC(self, v: int, S: Stack):
"""(连通域)基于DFS的双连通分量分解算法"""
assert (0 <= v) and (v < self.n)
self.clock += 1
V = self.V[v]
V.dTime = self.clock
V.fTime = self.clock
V.status = VStatus.DISCOVERD
S.push(v)
u = self.firstNbr(v)
while -1 < u:
U = self.V[u]
E = self.E[v][u]
if VStatus.UNDISCOVERD == U.status:
U.parent = v
E.type = EType.TREE
print(U, end='\t')
self.__BCC(u, S)
if self.fTime(u) < self.dTime(v):
V.fTime = min(V.fTime, U.fTime)
else:
while v != S.pop():
pass
S.push(v)
elif VStatus.DISCOVERD == U.status:
E.type = EType.BACKWARD
if u != V.parent:
V.fTime = min(V.fTime, U.dTime)
else:
E.type = EType.FORWARD if V.dTime < U.dTime else EType.CROSS
u = self.nextNbr(v, u)
V.status = VStatus.VISITED
def travPost_I(self):
"""二叉树后序遍历迭代"""
x = copy(self)
s = Stack([])
if x:
s.push(x)
while not s.empty():
if s.top() != x.parent:
self.gotoHLVEL(s)
x = s.pop()
print(x.data, end="->")
def travIn_I2(self):
"""二叉树中序遍历迭代版本2"""
x = copy(self)
s = Stack([])
while True:
if x:
s.push(x)
x = x.lc
elif not s.empty():
x = s.pop()
print(x.data, end="->")
x = x.rc
else:
break
def goAlongLeftBranch(self, s: Stack):
"""从当前节点出发,沿分支不断深入,直至没有左分支的节点"""
x = copy(self)
while x:
s.push(x)
x = x.lc