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Add kotlin code for the chapter of graph (#1102)
* feat(kotlin): add kotlin code for dynamic programming. * Update knapsack.kt * feat(kotlin): add kotlin codes for graph. * style(kotlin): reformatted the codes.
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121
codes/kotlin/chapter_graph/graph_adjacency_list.kt
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121
codes/kotlin/chapter_graph/graph_adjacency_list.kt
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/**
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* File: graph_adjacency_list.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_graph
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import utils.Vertex
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/* 基于邻接表实现的无向图类 */
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class GraphAdjList(edges: Array<Array<Vertex?>>) {
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// 邻接表，key：顶点，value：该顶点的所有邻接顶点
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val adjList: MutableMap<Vertex, MutableList<Vertex>> = HashMap()
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/* 构造函数 */
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init {
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// 添加所有顶点和边
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for (edge in edges) {
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addVertex(edge[0]!!);
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addVertex(edge[1]!!);
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addEdge(edge[0]!!, edge[1]!!);
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}
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}
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/* 获取顶点数量 */
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fun size(): Int {
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return adjList.size
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}
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/* 添加边 */
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fun addEdge(vet1: Vertex, vet2: Vertex) {
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if (!adjList.containsKey(vet1) || !adjList.containsKey(vet2) || vet1 == vet2)
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throw IllegalArgumentException()
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// 添加边 vet1 - vet2
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adjList[vet1]?.add(vet2)
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adjList[vet2]?.add(vet1);
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}
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/* 删除边 */
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fun removeEdge(vet1: Vertex, vet2: Vertex) {
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if (!adjList.containsKey(vet1) || !adjList.containsKey(vet2) || vet1 == vet2)
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throw IllegalArgumentException()
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// 删除边 vet1 - vet2
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adjList[vet1]?.remove(vet2);
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adjList[vet2]?.remove(vet1);
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}
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/* 添加顶点 */
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fun addVertex(vet: Vertex) {
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if (adjList.containsKey(vet))
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return
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// 在邻接表中添加一个新链表
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adjList[vet] = mutableListOf()
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}
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/* 删除顶点 */
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fun removeVertex(vet: Vertex) {
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if (!adjList.containsKey(vet))
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throw IllegalArgumentException()
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// 在邻接表中删除顶点 vet 对应的链表
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adjList.remove(vet);
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// 遍历其他顶点的链表，删除所有包含 vet 的边
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for (list in adjList.values) {
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list.remove(vet)
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}
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}
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/* 打印邻接表 */
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fun print() {
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println("邻接表 =")
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for (pair in adjList.entries) {
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val tmp = ArrayList<Int>()
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for (vertex in pair.value) {
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tmp.add(vertex.value)
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}
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println("${pair.key.value}: $tmp,")
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}
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}
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}
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/* Driver Code */
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fun main() {
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/* 初始化无向图 */
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val v: Array<Vertex?> = Vertex.valsToVets(intArrayOf(1, 3, 2, 5, 4))
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val edges = arrayOf(
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arrayOf(v[0], v[1]),
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arrayOf(v[0], v[3]),
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arrayOf(v[1], v[2]),
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arrayOf(v[2], v[3]),
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arrayOf(v[2], v[4]),
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arrayOf(v[3], v[4])
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)
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val graph = GraphAdjList(edges)
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println("\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 即 v[0], v[2]
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graph.addEdge(v[0]!!, v[2]!!)
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println("\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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// 顶点 1, 3 即 v[0], v[1]
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graph.removeEdge(v[0]!!, v[1]!!)
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println("\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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val v5 = Vertex(6)
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graph.addVertex(v5)
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println("\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 即 v[1]
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graph.removeVertex(v[1]!!)
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println("\n删除顶点 3 后，图为")
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graph.print()
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}
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131
codes/kotlin/chapter_graph/graph_adjacency_matrix.kt
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131
codes/kotlin/chapter_graph/graph_adjacency_matrix.kt
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/**
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* File: graph_adjacency_matrix.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_graph
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import utils.printMatrix
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/* 基于邻接矩阵实现的无向图类 */
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class GraphAdjMat(vertices: IntArray, edges: Array<IntArray>) {
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val vertices: MutableList<Int> = ArrayList() // 顶点列表，元素代表“顶点值”，索引代表“顶点索引”
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val adjMat: MutableList<MutableList<Int>> = ArrayList() // 邻接矩阵，行列索引对应“顶点索引”
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/* 构造函数 */
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init {
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// 添加顶点
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for (vertex in vertices) {
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addVertex(vertex)
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}
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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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for (edge in edges) {
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addEdge(edge[0], edge[1])
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}
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}
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/* 获取顶点数量 */
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fun size(): Int {
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return vertices.size
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}
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/* 添加顶点 */
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fun addVertex(value: Int) {
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val n = size()
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// 向顶点列表中添加新顶点的值
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vertices.add(value)
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// 在邻接矩阵中添加一行
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val newRow: MutableList<Int> = mutableListOf()
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for (j in 0..<n) {
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newRow.add(0)
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}
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adjMat.add(newRow)
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// 在邻接矩阵中添加一列
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for (row in adjMat) {
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row.add(0)
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}
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}
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/* 删除顶点 */
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fun removeVertex(index: Int) {
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if (index >= size()) throw IndexOutOfBoundsException()
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// 在顶点列表中移除索引 index 的顶点
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vertices.removeAt(index)
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// 在邻接矩阵中删除索引 index 的行
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adjMat.removeAt(index)
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// 在邻接矩阵中删除索引 index 的列
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for (row in adjMat) {
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row.removeAt(index)
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}
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}
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/* 添加边 */
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// 参数 i, j 对应 vertices 元素索引
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fun addEdge(i: Int, j: Int) {
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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) throw java.lang.IndexOutOfBoundsException()
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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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adjMat[i][j] = 1;
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adjMat[j][i] = 1;
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}
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/* 删除边 */
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// 参数 i, j 对应 vertices 元素索引
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fun removeEdge(i: Int, j: Int) {
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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) throw java.lang.IndexOutOfBoundsException()
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adjMat[i][j] = 0;
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adjMat[j][i] = 0;
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}
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/* 打印邻接矩阵 */
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fun print() {
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print("顶点列表 = ")
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println(vertices);
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println("邻接矩阵 =");
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printMatrix(adjMat)
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}
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}
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/* Driver Code */
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fun main() {
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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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val vertices = intArrayOf(1, 3, 2, 5, 4)
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val edges = arrayOf(
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intArrayOf(0, 1),
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intArrayOf(0, 3),
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intArrayOf(1, 2),
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intArrayOf(2, 3),
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intArrayOf(2, 4),
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intArrayOf(3, 4)
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)
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val graph = GraphAdjMat(vertices, edges)
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println("\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.addEdge(0, 2)
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println("\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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// 顶点 1, 3 的索引分别为 0, 1
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graph.removeEdge(0, 1)
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println("\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.addVertex(6)
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println("\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.removeVertex(1)
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println("\n删除顶点 3 后，图为")
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graph.print()
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}
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65
codes/kotlin/chapter_graph/graph_bfs.kt
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65
codes/kotlin/chapter_graph/graph_bfs.kt
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/**
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* File: graph_bfs.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_graph
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import utils.Vertex
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import java.util.*
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/* 广度优先遍历 */
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// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
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fun graphBFS(graph: GraphAdjList, startVet: Vertex): List<Vertex> {
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// 顶点遍历序列
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val res: MutableList<Vertex> = ArrayList()
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// 哈希表，用于记录已被访问过的顶点
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val visited: MutableSet<Vertex> = HashSet()
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visited.add(startVet)
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// 队列用于实现 BFS
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val que: Queue<Vertex> = LinkedList()
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que.offer(startVet)
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// 以顶点 vet 为起点，循环直至访问完所有顶点
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while (!que.isEmpty()) {
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val vet = que.poll() // 队首顶点出队
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res.add(vet) // 记录访问顶点
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// 遍历该顶点的所有邻接顶点
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for (adjVet in graph.adjList[vet]!!) {
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if (visited.contains(adjVet)) continue // 跳过已被访问的顶点
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que.offer(adjVet) // 只入队未访问的顶点
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visited.add(adjVet) // 标记该顶点已被访问
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}
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}
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// 返回顶点遍历序列
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return res
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}
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/* Driver Code */
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fun main() {
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/* 初始化无向图 */
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val v = Vertex.valsToVets(intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9))
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val edges = arrayOf(
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arrayOf(v[0], v[1]),
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arrayOf(v[0], v[3]),
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arrayOf(v[1], v[2]),
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arrayOf(v[1], v[4]),
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arrayOf(v[2], v[5]),
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arrayOf(v[3], v[4]),
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arrayOf(v[3], v[6]),
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arrayOf(v[4], v[5]),
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arrayOf(v[4], v[7]),
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arrayOf(v[5], v[8]),
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arrayOf(v[6], v[7]),
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arrayOf(v[7], v[8])
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)
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val graph = GraphAdjList(edges)
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println("\n初始化后，图为")
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graph.print()
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/* 广度优先遍历 */
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val res = graphBFS(graph, v[0]!!)
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println("\n广度优先遍历（BFS）顶点序列为")
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println(Vertex.vetsToVals(res))
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}
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62
codes/kotlin/chapter_graph/graph_dfs.kt
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62
codes/kotlin/chapter_graph/graph_dfs.kt
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/**
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* File: graph_dfs.kt
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* Created Time: 2024-01-25
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* Author: curtishd (1023632660@qq.com)
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*/
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package chapter_graph
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import utils.Vertex
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/* 深度优先遍历辅助函数 */
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fun dfs(
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graph: GraphAdjList,
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visited: MutableSet<Vertex?>,
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res: MutableList<Vertex?>,
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vet: Vertex?
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) {
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res.add(vet) // 记录访问顶点
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visited.add(vet) // 标记该顶点已被访问
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// 遍历该顶点的所有邻接顶点
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for (adjVet in graph.adjList[vet]!!) {
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if (visited.contains(adjVet)) continue // 跳过已被访问的顶点
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// 递归访问邻接顶点
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dfs(graph, visited, res, adjVet)
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}
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}
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/* 深度优先遍历 */
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// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
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fun graphDFS(
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graph: GraphAdjList,
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startVet: Vertex?
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): List<Vertex?> {
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// 顶点遍历序列
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val res: MutableList<Vertex?> = ArrayList()
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// 哈希表，用于记录已被访问过的顶点
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val visited: MutableSet<Vertex?> = HashSet()
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dfs(graph, visited, res, startVet)
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return res
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}
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/* Driver Code */
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fun main() {
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/* 初始化无向图 */
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val v = Vertex.valsToVets(intArrayOf(0, 1, 2, 3, 4, 5, 6))
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val edges = arrayOf(
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arrayOf(v[0], v[1]),
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arrayOf(v[0], v[3]),
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arrayOf(v[1], v[2]),
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arrayOf(v[2], v[5]),
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arrayOf(v[4], v[5]),
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arrayOf(v[5], v[6])
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)
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val graph = GraphAdjList(edges)
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println("\n初始化后，图为")
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graph.print()
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/* 深度优先遍历 */
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val res = graphDFS(graph, v[0])
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println("\n深度优先遍历（DFS）顶点序列为")
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println(Vertex.vetsToVals(res))
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}
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