diff --git a/problem-1/01-undirected-graph.png b/problem-1/01-undirected-graph.png
new file mode 100644
index 0000000..01b0afd
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diff --git a/problem-1/02-adjacency-matrix.png b/problem-1/02-adjacency-matrix.png
new file mode 100644
index 0000000..9589259
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diff --git a/problem-1/03-adjacency-list.png b/problem-1/03-adjacency-list.png
new file mode 100644
index 0000000..dee17e2
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diff --git a/problem-1/BFS.js b/problem-1/BFS.js
index c9a3539..7e0085b 100644
--- a/problem-1/BFS.js
+++ b/problem-1/BFS.js
@@ -1,24 +1,58 @@
+const { Queue } = require('../data-structure/Queue');
+const { Stack } = require('../data-structure/Stack');
+
 class BFS {
-  #marked = [];
+  #visited = [];
 
-  #edgeTo = [];
+  #previousVertexOf = [];
 
-  #s;
+  #startVertex;
 
-  constructor(graph, s) {
-    this.#marked = Array.from({ length: graph.v() }, () => false);
-    this.#edgeTo = Array.from({ length: graph.v() }, () => undefined);
-    this.#s = s;
-    this.#bfs(graph, s);
+  constructor(graph, startVertex) {
+    this.#visited = Array.from({ length: graph.sizeOfVertices() }, () => false);
+    this.#previousVertexOf = Array.from({ length: graph.sizeOfVertices() }, () => undefined);
+    this.#startVertex = startVertex;
+    this.#bfs(graph, startVertex);
   }
 
-  #bfs(graph, s) {
+  #bfs(graph, startVertex) {
+    const queue = new Queue();
+
+    this.#visited[startVertex] = true;
+    queue.enqueue(startVertex);
+
+    while (!queue.isEmpty()) {
+      const currentVertex = queue.dequeue();
+
+      for (const adjacentVertex of graph.adjacencyList(currentVertex)) {
+        if (!this.#visited[adjacentVertex]) {
+          this.#previousVertexOf[adjacentVertex] = currentVertex;
+          this.#visited[adjacentVertex] = true;
+          queue.enqueue(adjacentVertex);
+        }
+      }
+    }
   }
 
-  hasPathTo(v) {
+  // 해당 정점이 연결되어 있는지 안 되어 있는지 반환한다.
+  hasPathTo(vertex) {
+    return this.#visited[vertex];
   }
 
-  pathTo(v) {
+  pathTo(vertex) {
+    // 해당 정점에 연결된 정점이 없다 = 해당 정점으로 갈 경로가 없다.
+    if (!this.hasPathTo(vertex)) {
+      return;
+    }
+
+    const pathToVertex = new Stack();
+    for (let item = vertex; item !== this.#startVertex; item = this.#previousVertexOf[item]) {
+      pathToVertex.push(item);
+    }
+
+    pathToVertex.push(this.#startVertex);
+
+    return pathToVertex;
   }
 }
 
diff --git a/problem-1/ConnectedComponents.js b/problem-1/ConnectedComponents.js
index 43bad56..3c4e8ff 100644
--- a/problem-1/ConnectedComponents.js
+++ b/problem-1/ConnectedComponents.js
@@ -1,8 +1,36 @@
 class ConnectedComponents {
+  #visited = [];
+
+  #groupIds = [];
+
+  #groupId = 0;
+
   constructor(graph) {
+    this.#visited = Array.from({ length: graph.sizeOfVertices() }, () => false);
+    this.#groupIds = Array.from({ length: graph.sizeOfVertices() }, () => undefined);
+
+    for (let i = 0; i < graph.sizeOfVertices(); i++) {
+      if (!this.#visited[i]) {
+        this.#dfs(graph, i);
+        this.#groupId++;
+      }
+    }
+  }
+
+  #dfs(graph, vertex) {
+    this.#visited[vertex] = true;
+    this.#groupIds[vertex] = this.#groupId; // 아이디를 기록한다.
+
+    // 인접한 정점을 모두 확인한다.
+    for (const adjacentVertex of graph.adjacencyList(vertex)) {
+      if (!this.#visited[adjacentVertex]) {
+        this.#dfs(graph, adjacentVertex);
+      }
+    }
   }
 
-  connected(v, w) {
+  connected(vertex1, vertex2) {
+    return this.#groupIds[vertex1] === this.#groupIds[vertex2];
   }
 }
 
diff --git a/problem-1/DFS.js b/problem-1/DFS.js
index ed14f13..ab65bf8 100644
--- a/problem-1/DFS.js
+++ b/problem-1/DFS.js
@@ -1,26 +1,50 @@
 const { Stack } = require('../data-structure/Stack');
 
 class DFS {
-  #marked = [];
+  #visited = [];
 
-  #edgeTo = [];
+  #previousVertexOf = [];
 
-  #s;
+  #startVertex;
 
-  constructor(graph, s) {
-    this.#marked = Array.from({ length: graph.v() }, () => false);
-    this.#edgeTo = Array.from({ length: graph.v() }, () => undefined);
-    this.#s = s;
-    this.#dfs(graph, s);
+  constructor(graph, startVertex) {
+    this.#visited = Array.from({ length: graph.sizeOfVertices() }, () => false);
+    this.#previousVertexOf = Array.from({ length: graph.sizeOfVertices() }, () => undefined);
+    this.#startVertex = startVertex;
+    this.#dfs(graph, startVertex);
   }
 
-  #dfs(grpah, v) {
+  #dfs(graph, currentVertex) {
+    // 선택한 정점의 방문 여부 체크
+    this.#visited[currentVertex] = true;
+
+    for (const adjacentVertex of graph.adjacencyList(currentVertex)) {
+      if (!this.#visited[adjacentVertex]) { // 방문한 적 없는 인접 정점일 경우
+        this.#previousVertexOf[adjacentVertex] = currentVertex; // currentVertex 로부터 방문했다고 기록한다.
+        this.#dfs(graph, adjacentVertex);
+      }
+    }
   }
 
-  hasPathTo(v) {
+  // 해당 정점이 연결되어 있는지 안 되어 있는지 반환한다.
+  hasPathTo(vertex) {
+    return this.#visited[vertex];
   }
 
-  pathTo(v) {
+  pathTo(vertex) {
+    // 해당 정점에 연결된 정점이 없다 = 해당 정점으로 갈 경로가 없다.
+    if (!this.hasPathTo(vertex)) {
+      return;
+    }
+
+    const pathToVertex = new Stack();
+    for (let item = vertex; item !== this.#startVertex; item = this.#previousVertexOf[item]) {
+      pathToVertex.push(item);
+    }
+
+    pathToVertex.push(this.#startVertex);
+
+    return pathToVertex;
   }
 }
 
diff --git a/problem-1/Graph.js b/problem-1/Graph.js
index 37762f0..b7dd3cf 100644
--- a/problem-1/Graph.js
+++ b/problem-1/Graph.js
@@ -1,35 +1,36 @@
 const { Bag } = require('../data-structure/Bag');
 
 class Graph {
-  #v;
+  #numberOfVertices;
 
-  #e;
+  #numberOfEdges;
 
-  #adj = [];
+  #adjacencyList = [];
 
-  constructor(v) {
-    this.#v = v;
-    for (let i = 0; i < this.#v; i++) {
-      this.#adj[i] = new Bag();
+  constructor(numberOfVertices) {
+    this.#numberOfVertices = numberOfVertices;
+
+    for (let i = 0; i < this.#numberOfVertices; i++) {
+      this.#adjacencyList[i] = new Bag();
     }
   }
 
-  addEdge(v, w) {
-    this.#adj[v].add(w);
-    this.#adj[w].add(v);
-    this.#e++;
+  addEdge(source, destination) {
+    this.#adjacencyList[source].add(destination);
+    this.#adjacencyList[destination].add(source);
+    this.#numberOfEdges++;
   }
 
-  adj(v) {
-    return this.#adj[v];
+  adjacencyList(vertex) {
+    return this.#adjacencyList[vertex];
   }
 
-  v() {
-    return this.#v;
+  sizeOfVertices() {
+    return this.#numberOfVertices;
   }
 
-  e() {
-    return this.#e;
+  sizeOfEdges() {
+    return this.#numberOfEdges;
   }
 }
 
diff --git a/problem-1/README.md b/problem-1/README.md
index 5154fc5..ab54969 100644
--- a/problem-1/README.md
+++ b/problem-1/README.md
@@ -20,12 +20,17 @@
 8 1
 4 1
 ```
+![01-undirected-graph.png](01-undirected-graph.png)
 
 2. 위의 그려진 그래프를 인접 행렬로 표현되는 데이터 구조를 그림으로 그려주세요.
 
+![02-adjacency-matrix.png](02-adjacency-matrix.png)
+
 3. 위의 그려진 그래프를 인접 리스트로 표현되는 데이터 구조로 그림으로
    그려주세요.
 
+![03-adjacency-list.png](03-adjacency-list.png)
+
 4. 위의 그래프에서 10번 노드에서 6번 노드로 DFS를 할 때 어떤 경로를 통해서 가는지 구하는 함수를 구현해 주세요.
 
 5. 마찬가지로 10번 노드에서 6번 노드로 BFS를 할 때 어떤 경로를 통해서 가는지 함수를 구하는 구현해 주세요.
diff --git a/problem-2/Diagraph.js b/problem-2/Diagraph.js
index a7e41bb..e559d31 100644
--- a/problem-2/Diagraph.js
+++ b/problem-2/Diagraph.js
@@ -1,34 +1,34 @@
 const { Bag } = require('../data-structure/Bag');
 
 class Diagraph {
-  #v;
+  #numberOfVertices;
 
-  #e;
+  #numberOfEdges;
 
-  #adj = [];
+  #adjacencyList = [];
 
-  constructor(v) {
-    this.#v = v;
-    for (let i = 0; i < this.#v; i++) {
-      this.#adj[i] = new Bag();
+  constructor(numberOfVertices) {
+    this.#numberOfVertices = numberOfVertices;
+    for (let i = 0; i < this.#numberOfVertices; i++) {
+      this.#adjacencyList[i] = new Bag();
     }
   }
 
-  addEdge(v, w) {
-    this.#adj[v].add(w);
-    this.#e++;
+  addEdge(source, destination) {
+    this.#adjacencyList[source].add(destination);
+    this.#numberOfEdges++;
   }
 
-  adj(v) {
-    return this.#adj[v];
+  adjacencyList(vertex) {
+    return this.#adjacencyList[vertex];
   }
 
-  v() {
-    return this.#v;
+  sizeOfVertices() {
+    return this.#numberOfVertices;
   }
 
-  e() {
-    return this.#e;
+  sizeOfEdges() {
+    return this.#numberOfEdges;
   }
 }
 
diff --git a/problem-2/DirectedCycle.js b/problem-2/DirectedCycle.js
index d08ca09..13d37ee 100644
--- a/problem-2/DirectedCycle.js
+++ b/problem-2/DirectedCycle.js
@@ -1,27 +1,63 @@
 const { Stack } = require('../data-structure/Stack');
 
 class DirectedCycle {
-  #marked = [];
+  #visited = [];
 
-  #edgeTo = [];
+  #previousVertexOf = [];
 
-  #onStack = [];
+  #visiting = [];
 
   #cycle;
 
   constructor(diagraph) {
-    this.#marked = Array.from({ length: diagraph.v() }, () => false);
-    this.#edgeTo = Array.from({ length: diagraph.v() }, () => undefined);
-    this.#onStack = Array.from({ length: diagraph.v() }, () => false);
+    this.#visited = Array.from({ length: diagraph.sizeOfVertices() }, () => false);
+    this.#previousVertexOf = Array.from({ length: diagraph.sizeOfVertices() }, () => undefined);
+    this.#visiting = Array.from({ length: diagraph.sizeOfVertices() }, () => false);
+
+    for (let vertex = 0; vertex < diagraph.sizeOfVertices(); vertex++) {
+      if (!this.#visited[vertex]) {
+        this.#dfs(diagraph, vertex);
+      }
+    }
   }
 
-  #dfs(diagraph, v) {
+  #dfs(diagraph, vertex) {
+    this.#visited[vertex] = true; // 방문했음을 체크
+    this.#visiting[vertex] = true; // 현재 방문 중임을 체크
+
+    // todo : 인접한 정점을 돌면서 순환 경로(cycle)이 있는지 체크하기
+    for (const adjacentVertex of diagraph.adjacencyList(vertex)) {
+      if (this.hasCycle()) { // 이미 순환경로가 있다면 종료
+        return;
+      }
+
+      if (!this.#visited[adjacentVertex]) { // 만약 방문한 적 없는 인접 정점이라면
+        this.#previousVertexOf[adjacentVertex] = vertex; // 현재 정점에서 방문했다고 기록
+        this.#dfs(diagraph, adjacentVertex); // 해당 인접 정점에 인접하는 정점을 돌면서 재귀적으로 실행
+      } else if (this.#visiting[adjacentVertex]) {
+        // 현재의 인접 정점이 방문도 했고, 현재 방문중인 정점이라면 -> 순환한다는 것
+        this.#cycle = new Stack(); // 순환 경로를 기록할 stack 생성
+
+        for (let v = vertex; v !== adjacentVertex; v = this.#previousVertexOf[v]) {
+          // 현재 정점이 어디에서부터 왔는지 거슬러 올라가면서 순환 경로 스택에 추가한다.
+          this.#cycle.push(v);
+        }
+
+        // 목적지와 출발지 담기
+        this.#cycle.push(adjacentVertex);
+        this.#cycle.push(vertex);
+      }
+    }
+
+    this.#visiting[vertex] = false;
   }
 
   hasCycle() {
+    return !!this.#cycle;
   }
 
   cycle() {
+    return this.#cycle;
   }
 }
 
diff --git a/problem-2/DirectedDFS.js b/problem-2/DirectedDFS.js
index 5c9108a..221b6bc 100644
--- a/problem-2/DirectedDFS.js
+++ b/problem-2/DirectedDFS.js
@@ -1,15 +1,26 @@
 class DirectedDFS {
-  #marked = [];
+  #visited = [];
 
-  constructor(diagraph, s) {
-    this.#marked = Array.from({ length: diagraph.v() }, () => false);
-    this.#dfs(diagraph, s);
+  constructor(diagraph, startVertex) {
+    this.#visited = Array.from({ length: diagraph.sizeOfVertices() }, () => false);
+    this.#dfs(diagraph, startVertex);
   }
 
-  #dfs(diagraph, v) {
+  #dfs(diagraph, vertex) {
+    // 현재 정점을 방문했다고 표시
+    this.#visited[vertex] = true;
+
+    // 인접한 정점에서 체크하기
+    for (const adjacentVertex of diagraph.adjacencyList(vertex)) {
+      // 현재의 인접한 정점에 방문한 적이 없을 경우
+      if (!this.#visited[adjacentVertex]) {
+        this.#dfs(diagraph, adjacentVertex);
+      }
+    }
   }
 
-  reachable(v) {
+  reachable(vertex) {
+    return this.#visited[vertex]; // 방문한 적이 있는 정점이라면 도달 가능한 것.
   }
 }
 
diff --git a/problem-2/README.md b/problem-2/README.md
index f81c573..902b2bc 100644
--- a/problem-2/README.md
+++ b/problem-2/README.md
@@ -21,6 +21,7 @@
 8 1
 4 1
 ```
+![directed-graph.png](directed-graph.png)
 
 2. 도달성을 확인하는 객체 `DirectedDFS.js`를 완성해 주세요.
 
diff --git a/problem-2/directed-graph.png b/problem-2/directed-graph.png
new file mode 100644
index 0000000..dc3136f
Binary files /dev/null and b/problem-2/directed-graph.png differ