Create dfs.go

Author: tsyber1an

Diff for: dfs.go

@@ -0,0 +1,46 @@
+func IsNonCyclic(edges [][]int) bool {
+    adjList := make(map[int][]int)
+    for _, edge := range edges{
+        node1, node2 := edge[0], edge[1]
+_, ok := adjList[node1]
+        if !ok{
+            adjList[node1] = []int{node2}
+        }else{
+            adjList[node1] = append(adjList[node1], node2)
+        }
+    } 
+    visited := make(map[int]int)
+    for node:= range adjList{
+        if visited[node] == 1{
+            continue
+        }
+        if !dfs(node, adjList, &visited){
+            return false
+        }
+    }
+    return true
+}
+func dfs(node int, adjList map[int][]int, visited *map[int]int) bool { 
+    neighbourArr, ok := adjList[node]
+    if !ok{
+        return true
+    }
+    
+    if (*visited)[node] == -1{
+        return false
+    }
+    
+    if (*visited)[node] == 1{
+        return true
+    }
+    
+    (*visited)[node] = -1
+    
+    for _, neighbour := range neighbourArr{
+        if !dfs(neighbour, adjList, visited){
+            return false
+        }
+    }
+    (*visited)[node] = 1
+    return true
+}