examples: add more graphs examples, fix typo (#17113)

examples/graphs/bfs2.v

@@ -60,9 +60,8 @@ fn departure(mut queue []string) string {
 // Creating aa map to initialize with of visited nodes .... all with false in the init
 // so these nodes are NOT VISITED YET
 fn visited_init(a_graph map[string][]string) map[string]bool {
-	mut array_of_keys := a_graph.keys() // get all keys of this map
 	mut temp := map[string]bool{} // attention in these initializations with maps
-	for i in array_of_keys {
+	for i, _ in a_graph {
 		temp[i] = false
 	}
 	return temp

examples/graphs/dfs.v

@@ -27,7 +27,7 @@ fn main() {
 	path_01 := depth_first_search_path(graph_01, 'A', 'F')
 	println('\n Graph_01: a first path from node A to node F is: ${path_01.reverse()}')
 	path_02 := depth_first_search_path(graph_02, 'A', 'H')
-	println('\n Graph_02: a first path from node A to node F is: ${path_02.reverse()}')
+	println('\n Graph_02: a first path from node A to node H is: ${path_02.reverse()}')
 }
 
 // Depth-First Search (BFS) allows you to find a path between two nodes in the graph.
@@ -74,9 +74,8 @@ fn depth_first_search_path(graph map[string][]string, start string, target strin
 // Creating aa map to initialize with of visited nodes .... all with false in the init
 // so these nodes are NOT VISITED YET
 fn visited_init(a_graph map[string][]string) map[string]bool {
-	mut array_of_keys := a_graph.keys() // get all keys of this map
 	mut temp := map[string]bool{} // attention in these initializations with maps
-	for i in array_of_keys {
+	for i, _ in a_graph {
 		temp[i] = false
 	}
 	return temp

examples/graphs/dfs2.v

@@ -0,0 +1,83 @@
+// Author: CCS & KeitoTobi1
+// Backtracking Supported.
+fn main() {
+	// Adjacency matrix as a map	
+	// Example 01
+	graph_01 := {
+		'A': ['B', 'C']
+		'B': ['A', 'D', 'E']
+		'C': ['A', 'F']
+		'D': ['B']
+		'E': ['F', 'B', 'F']
+		'F': ['C', 'E']
+	}
+
+	// Example 02
+	graph_02 := {
+		'A': ['B', 'C', 'D']
+		'B': ['E']
+		'C': ['F']
+		'D': ['E']
+		'E': ['H']
+		'F': ['H']
+		'G': ['H']
+		'H': ['E', 'F', 'G']
+	}
+
+	// println('Graph: $graph')
+	path_01 := depth_first_search_path(graph_01, 'A', 'F')
+	println('\n Graph_01: all path pattern from node A to node F is:')
+	print_pattern(path_01)
+	path_02 := depth_first_search_path(graph_02, 'A', 'H')
+	println('\n Graph_02: all path pattern from node A to node F is:')
+	print_pattern(path_02)
+}
+
+fn depth_first_search_path(adj map[string][]string, start string, target string) [][]string {
+	mut sol := Solution{}
+	mut path := []string{}
+	mut visited := visited_init(adj)
+
+	// false ... not visited yet: {'A': false, 'B': false, 'C': false, 'D': false, 'E': false}
+	sol.find_pattern(adj, mut visited, start, target, mut path)
+	return sol.pattern
+}
+
+struct Solution {
+pub mut:
+	pattern [][]string
+}
+
+fn (mut s Solution) find_pattern(adj map[string][]string, mut visited map[string]bool, node string, target string, mut path []string) {
+	path << node
+	visited[node] = true
+	if node == target {
+		print('\n Founded pattern: ${path}')
+		s.pattern << [path]
+	}
+	print('\n Exploring of node ${node} (true/false): ${adj[node]}')
+	for i, _ in adj[node] {
+		if !visited[adj[node][i]] {
+			mut temp := path.clone()
+			s.find_pattern(adj, mut visited, adj[node][i], target, mut temp)
+		}
+	}
+	visited[node] = false
+	print('\n Current: ${node} (only not visited) \n Visited: ${visited}')
+}
+
+fn print_pattern(pat [][]string) {
+	for p in pat {
+		println(p)
+	}
+}
+
+// Creating aa map to initialize with of visited nodes .... all with false in the init
+// so these nodes are NOT VISITED YET
+fn visited_init(adj map[string][]string) map[string]bool {
+	mut temp := map[string]bool{}
+	for i, _ in adj {
+		temp[i] = false
+	}
+	return temp
+}