Merge pull request deutranium#218 from InLieuOfLuna/master

Added depth first search in kotlin

Author: deutranium

searchingAlgo/DepthFirstSearch/depthFirstSearch.kt

@@ -0,0 +1,38 @@
+/**
+ * Creates a Graph with [size] nodes
+ * @param init constructor for adding the edges of the nodes delegated to the instances
+ */
+class Graph(size: Int, init: Graph.() -> Unit) {
+    val adjacency: Array<MutableList<Int>> = Array(size) { ArrayList() }
+
+    init { init() }
+
+    fun addEdge(node: Int, to: Int) = adjacency[node].add(to)
+}
+
+/**
+ * Prints the route taken when exploring the [graph] starting from [current]
+ * @param searched an array of booleans relating to whether the relating nodes have been searched
+ */
+fun depthFirstSearch(graph: Graph, current: Int, searched: Array<Boolean> = Array(graph.adjacency.size) { false }) {
+    if(!searched[current]) {
+        searched[current] = true
+        print("$current ")
+        for (next in graph.adjacency[current]) {
+            depthFirstSearch(graph, next, searched)
+        }
+    }
+}
+
+fun main() {
+    val graph = Graph(4) {
+        addEdge(0, 1)
+        addEdge(0, 2)
+        addEdge(1, 2)
+        addEdge(2, 0)
+        addEdge(2, 3)
+        addEdge(3, 3)
+    }
+    println("Following is Depth First Traversal " + "(Starting from vertex 2)")
+    depthFirstSearch(graph, 2)
+}