depth-first-search.js

/*
Represent the following graph as an adjacency list.
write a dfs function that takes the adjacency list, a start node, and a target node. return true if it's in the graph, and false if it is not

               A
            /	  \
	        F       B
	       /       / \
	      G       D    C
     	/ | \     |
     J  I  H	  E
     
     
     
     
     
        A
       /  \
      B    C
     / \    \
    D   E    H
       / \   
      F   G
*/



var nodeNotVisited = (list,item) => {
	if (list.indexOf(item) === -1) {
		return true;
	}
	return false;
};

const graph1 = {
  "A": ["F","B"],
  "B": ["D","C"],
  "C": [],
  "D": ["E"],
  "E": [],
  "F": ["G"],
  "G": ["J","I","H"],
  "H": [],
  "I": [],
  "J": []
};


const graph2 = {
	A: ['B','C'],
	B: ['D','E'],
	C: ['H'],
	D: [],
	E: ['F','G'],
	F: [],
	G: [],
	H: ['G']
}


var dfs = (graph,node,targetNode) => {
  let visited   = [];
	let stack     = [];
	stack.push(node);
	visited.push(node);
	while (stack.length > 0) {
    let node = stack.pop();
    let neighbors = graph[node];
    for(let node of neighbors){
    	if (nodeNotVisited(visited,node)){
    		if (node === targetNode){
    			return true;
    		}
    		else{
    			visited.push(node);
    			stack.push(node);
    		}
    	}
    }
   }
   console.log(visited)
   return false;
};

dfs(graph2,"A", "z");