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Commit 506c5c1

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Euler图的实现和Euler Loop algorithm
1 parent d31f179 commit 506c5c1

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10 files changed

+419
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‎Euler/EulerLoop.py‎

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"""
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@author: Alex
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@contact: 1272296763@qq.com or jakinmili@gmail.com
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@file: EulerLoop.py
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@time: 2019年10月20日 19:12
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"""
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class EulerLoop:
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def __init__(self, filename):
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self.V = 0 # 顶点数
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self.E = 0 # 边数
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self.adj = None
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self.__cccount = 0 # 联通分量
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self.__visited = None
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with open(filename) as f:
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line_num = 0 # 第一行是顶点数和边数
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for line in f:
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if line_num == 0:
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v, e = line.strip().split()
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self.V = int(v)
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self.E = int(e)
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self.adj = [[] for i in range(self.V)] # 创建二维数组即邻接表
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else:
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# 读取边 写入邻接表
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v1, v2 = line.strip().split()
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# 转化为整数
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v1 = int(v1)
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v2 = int(v2)
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self.adj[v1].append(v2)
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self.adj[v2].append(v1)
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line_num += 1
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# dfs遍历
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self.graphDFS()
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def get_graph_information(self):
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"""
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打印图的邻接表
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:return:
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"""
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print("V={}, E={}".format(self.V, self.E))
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for i, v in enumerate(self.adj):
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print("{} : {}".format(i, v))
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def validateVertex(self, v):
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"""
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验证顶点取值
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:param v:
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:return:
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"""
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if v<0 or v>=self.V:
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raise ValueError("v值超出范围")
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def hasEdge(self, v, w):
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"""
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判断两个顶点是否存在
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:param v: 第一个顶点
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:param w: 第二个顶点
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:return: true or false
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"""
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self.validateVertex(v)
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self.validateVertex(w)
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return w in self.adj[v]
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def degree(self, v):
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"""
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求某个顶点的度
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:param v:
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:return:
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"""
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self.validateVertex(v)
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return len(self.adj[v])
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def graphDFS(self):
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visited = [-1 for i in range(self.V)]
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cccount = 0 # 联通分量
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def dfs(v, ccid):
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# 标记v顶点已经遍历过了
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visited[v] = ccid
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# 添加
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for w in self.adj[v]:
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if visited[w] == -1:
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dfs(w, ccid)
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# 此刻对某个顶点的邻点已经遍历结束
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# 顾及到有多个联通分量,对每个顶点都做DFS
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for i in range(self.V):
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if visited[i] == -1:
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dfs(i, cccount)
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cccount += 1
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self.__cccount = cccount
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self.__visited = visited
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def get_cccount(self):
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"""
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获取该图的联通分量大小
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:return:
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"""
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return self.__cccount
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def hasEulerLoop(self):
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# 联通分量判断
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if self.get_cccount() > 1:
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print("该图不存在欧拉回路(Euler Loop)")
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return False
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# 度数判断
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for v in range(self.V):
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if self.degree(v) % 2 == 1:
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print("该图不存在欧拉回路(Euler Loop)")
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return False
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print("该图存在欧拉回路(Euler Loop)")
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return True
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if __name__ == '__main__':
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ELD = EulerLoopDetection("g.txt")
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ELD.get_graph_information()
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ELD.hasEulerLoop()
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ELD2 = EulerLoopDetection("g2.txt")
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ELD2.get_graph_information()
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ELD2.hasEulerLoop()

‎Euler/EulerLoopDetection.py‎

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"""
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@author: Alex
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@contact: 1272296763@qq.com or jakinmili@gmail.com
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@file: EulerLoopDetection.py
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@time: 2019年10月20日 19:12
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"""
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class EulerLoopDetection:
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def __init__(self, filename):
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self.V = 0 # 顶点数
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self.E = 0 # 边数
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self.adj = None
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self.__cccount = 0 # 联通分量
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self.__visited = None
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with open(filename) as f:
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line_num = 0 # 第一行是顶点数和边数
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for line in f:
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if line_num == 0:
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v, e = line.strip().split()
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self.V = int(v)
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self.E = int(e)
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self.adj = [[] for i in range(self.V)] # 创建二维数组即邻接表
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else:
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# 读取边 写入邻接表
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v1, v2 = line.strip().split()
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# 转化为整数
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v1 = int(v1)
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v2 = int(v2)
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self.adj[v1].append(v2)
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self.adj[v2].append(v1)
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line_num += 1
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# dfs遍历
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self.graphDFS()
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def get_graph_information(self):
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"""
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打印图的邻接表
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:return:
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"""
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print("V={}, E={}".format(self.V, self.E))
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for i, v in enumerate(self.adj):
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print("{} : {}".format(i, v))
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def validateVertex(self, v):
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"""
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验证顶点取值
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:param v:
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:return:
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"""
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if v<0 or v>=self.V:
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raise ValueError("v值超出范围")
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def hasEdge(self, v, w):
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"""
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判断两个顶点是否存在
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:param v: 第一个顶点
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:param w: 第二个顶点
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:return: true or false
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"""
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self.validateVertex(v)
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self.validateVertex(w)
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return w in self.adj[v]
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def degree(self, v):
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"""
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求某个顶点的度
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:param v:
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:return:
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"""
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self.validateVertex(v)
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return len(self.adj[v])
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def graphDFS(self):
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visited = [-1 for i in range(self.V)]
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cccount = 0 # 联通分量
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def dfs(v, ccid):
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# 标记v顶点已经遍历过了
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visited[v] = ccid
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# 添加
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for w in self.adj[v]:
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if visited[w] == -1:
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dfs(w, ccid)
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# 此刻对某个顶点的邻点已经遍历结束
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# 顾及到有多个联通分量,对每个顶点都做DFS
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for i in range(self.V):
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if visited[i] == -1:
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dfs(i, cccount)
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cccount += 1
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self.__cccount = cccount
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self.__visited = visited
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def get_cccount(self):
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"""
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获取该图的联通分量大小
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:return:
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"""
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return self.__cccount
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def hasEulerLoop(self):
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# 联通分量判断
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if self.get_cccount() > 1:
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print("该图不存在欧拉回路(Euler Loop)")
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return False
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# 度数判断
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for v in range(self.V):
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if self.degree(v) % 2 == 1:
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print("该图不存在欧拉回路(Euler Loop)")
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return False
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print("该图存在欧拉回路(Euler Loop)")
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return True
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if __name__ == '__main__':
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ELD = EulerLoopDetection("g.txt")
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ELD.get_graph_information()
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ELD.hasEulerLoop()
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ELD2 = EulerLoopDetection("g2.txt")
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ELD2.get_graph_information()
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ELD2.hasEulerLoop()

‎Euler/__init__.py‎

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"""
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@author: Alex
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@contact: 1272296763@qq.com or jakinmili@gmail.com
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@file: __init__.py.py
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@time: 2019年11月15日 13:03
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"""
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‎Euler/g.txt‎

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5 6
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0 1
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0 2
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1 2
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2 3
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2 4
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3 4

‎Euler/g2.txt‎

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11 15
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0 1
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0 3
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1 2
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1 4
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1 5
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2 5
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3 4
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4 5
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4 6
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5 7
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6 7
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7 8
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7 9
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8 10
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9 10

‎WeightedGraph/__init__.py‎

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"""
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@author: Alex
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@contact: 1272296763@qq.com or jakinmili@gmail.com
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@file: __init__.py.py
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@time: 2019年11月16日 16:31
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"""
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‎WeightedGraph/g.txt‎

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7 12
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0 1 2
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0 3 7
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0 5 2
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1 2 1
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1 3 4
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1 4 3
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1 5 5
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2 4 4
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2 5 4
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3 4 1
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3 6 5
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4 6 7

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