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=begin
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File: graph_adjacency_matrix.rb
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Created Time: 2024-04-25
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Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
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=end
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require_relative '../utils/print_util'
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### 基于邻接矩阵实现的无向图类 ###
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class GraphAdjMat
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def initialize(vertices, edges)
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### 构造方法 ###
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# 顶点列表，元素代表“顶点值”，索引代表“顶点索引”
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@vertices = []
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# 邻接矩阵，行列索引对应“顶点索引”
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@adj_mat = []
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# 添加顶点
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vertices.each { |val| add_vertex(val) }
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# 添加边
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# 请注意，edges 元素代表顶点索引，即对应 vertices 元素索引
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edges.each { |e| add_edge(e[0], e[1]) }
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end
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### 获取顶点数量 ###
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def size
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@vertices.length
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end
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### 添加顶点 ###
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def add_vertex(val)
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n = size
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# 向顶点列表中添加新顶点的值
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@vertices << val
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# 在邻接矩阵中添加一行
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new_row = Array.new(n, 0)
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@adj_mat << new_row
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# 在邻接矩阵中添加一列
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@adj_mat.each { |row| row << 0 }
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end
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### 删除顶点 ###
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def remove_vertex(index)
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raise IndexError if index >= size
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# 在顶点列表中移除索引 index 的顶点
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@vertices.delete_at(index)
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# 在邻接矩阵中删除索引 index 的行
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@adj_mat.delete_at(index)
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# 在邻接矩阵中删除索引 index 的列
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@adj_mat.each { |row| row.delete_at(index) }
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end
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### 添加边 ###
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def add_edge(i, j)
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# 参数 i, j 对应 vertices 元素索引
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# 索引越界与相等处理
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if i < 0 || j < 0 || i >= size || j >= size || i == j
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raise IndexError
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end
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# 在无向图中，邻接矩阵关于主对角线对称，即满足 (i, j) == (j, i)
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@adj_mat[i][j] = 1
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@adj_mat[j][i] = 1
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end
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### 删除边 ###
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def remove_edge(i, j)
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# 参数 i, j 对应 vertices 元素索引
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# 索引越界与相等处理
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if i < 0 || j < 0 || i >= size || j >= size || i == j
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raise IndexError
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end
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@adj_mat[i][j] = 0
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@adj_mat[j][i] = 0
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end
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### 打印邻接矩阵 ###
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def __print__
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puts "顶点列表 = #{@vertices}"
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puts '邻接矩阵 ='
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print_matrix(@adj_mat)
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end
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end
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### Driver Code ###
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if __FILE__ == $0
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# 初始化无向图
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# 请注意，edges 元素代表顶点索引，即对应 vertices 元素索引
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vertices = [1, 3, 2, 5, 4]
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edges = [[0, 1], [0, 3], [1, 2], [2, 3], [2, 4], [3, 4]]
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graph = GraphAdjMat.new(vertices, edges)
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puts "\n初始化后，图为"
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graph.__print__
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# 添加边
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# 顶点 1, 2 的索引分别为 0, 2
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graph.add_edge(0, 2)
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puts "\n添加边 1-2 后，图为"
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graph.__print__
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# 删除边
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# 定点 1, 3 的索引分别为 0, 1
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graph.remove_edge(0, 1)
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puts "\n删除边 1-3 后，图为"
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graph.__print__
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# 添加顶点
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graph.add_vertex(6)
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puts "\n添加顶点 6 后，图为"
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graph.__print__
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# 删除顶点
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# 顶点 3 的索引为 1
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graph.remove_vertex(1)
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puts "\n删除顶点 3 后，图为"
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graph.__print__
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end
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