diff --git "a/13_\354\265\234\353\213\250\352\262\275\353\241\234/1238.cpp" "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/1238.cpp"
new file mode 100644
index 0000000..092b77f
--- /dev/null
+++ "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/1238.cpp"
@@ -0,0 +1,74 @@
+//13_최단경로 필수 2번:1238.cpp
+
+#include <iostream>
+#include <vector>
+#include <queue>
+#include <climits>
+
+using namespace std;
+
+const int INF = INT_MAX;
+
+int main() 
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int v, e, x;
+    cin >> v >> e >> x;
+
+    vector<vector<pair<int, int>>> graph(v + 1);
+
+    for (int i = 0; i < e; ++i) 
+    {
+        int a, b, cost;
+        cin >> a >> b >> cost;
+        graph[a].emplace_back(b, cost);
+    }
+
+    auto dijkstra = [&](int start) 
+  {
+        priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
+        vector<int> distance(v + 1, INF);
+
+        pq.push({0, start});
+        distance[start] = 0;
+
+        while (!pq.empty()) 
+        {
+            int dist = pq.top().first;
+            int now = pq.top().second;
+            pq.pop();
+
+            if (distance[now] < dist) continue;
+
+            for (const auto& edge : graph[now]) 
+            {
+                int node_index = edge.first;
+                int node_cost = edge.second;
+                int cost = dist + node_cost;
+
+                if (distance[node_index] > cost) 
+                {
+                    distance[node_index] = cost;
+                    pq.push({cost, node_index});
+                }
+            }
+        }
+
+        return distance;
+    };
+
+    int result = 0;
+  
+    for (int i = 1; i <= v; ++i) 
+    {
+        vector<int> go = dijkstra(i);
+        vector<int> back = dijkstra(x);
+        result = max(result, go[x] + back[i]);
+    }
+
+    cout << result << "\n";
+
+    return 0;
+}
diff --git "a/13_\354\265\234\353\213\250\352\262\275\353\241\234/15685.cpp" "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/15685.cpp"
new file mode 100644
index 0000000..f43621f
--- /dev/null
+++ "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/15685.cpp"
@@ -0,0 +1,65 @@
+//13_최단경로 필수 1번:15685.cpp
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+bool map[101][101] = {false};
+int dx[] = {1, 0, -1, 0};
+int dy[] = {0, -1, 0, 1};
+int ans = 0;
+
+void dragonCurve(int x, int y, int d, int g);
+
+int main() 
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    int n;
+    cin >> n;
+
+    for (int i = 0; i < n; i++) 
+    {
+        int x, y, d, g;
+        cin >> x >> y >> d >> g;
+        dragonCurve(x, y, d, g);
+    }
+
+    for (int i = 0; i < 100; i++) 
+    {
+        for (int j = 0; j < 100; j++) 
+        {
+            if (map[i][j] && map[i][j + 1] && map[i + 1][j] && map[i + 1][j + 1]) 
+            {
+                ans++;
+            }
+        }
+    }
+
+    cout << ans << "\n";
+
+    return 0;
+}
+
+void dragonCurve(int x, int y, int d, int g) 
+{
+    vector<int> d_list;
+    d_list.push_back(d);
+
+    for (int i = 1; i <= g; i++) 
+    {
+        for (int j = d_list.size() - 1; j >= 0; j--) {
+            d_list.push_back((d_list[j] + 1) % 4);
+        }
+    }
+
+    map[y][x] = true;
+    for (int direction : d_list) 
+    {
+        x += dx[direction];
+        y += dy[direction];
+        map[y][x] = true;
+    }
+}
diff --git "a/13_\354\265\234\353\213\250\352\262\275\353\241\234/1865.cpp" "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/1865.cpp"
new file mode 100644
index 0000000..d48135d
--- /dev/null
+++ "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/1865.cpp"
@@ -0,0 +1,2 @@
+//13_최단경로 도전 2번:1865.cpp
+
diff --git "a/13_\354\265\234\353\213\250\352\262\275\353\241\234/2458.cpp" "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/2458.cpp"
new file mode 100644
index 0000000..c0fbdf5
--- /dev/null
+++ "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/2458.cpp"
@@ -0,0 +1,58 @@
+//13_필수3: 2458.cpp
+
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+const int INF = 999999999;
+
+int main() 
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n, m;
+    cin >> n >> m;
+
+    vector<vector<int>> dist(n + 1, vector<int>(n + 1, INF));
+
+    for (int i = 1; i <= m; ++i) 
+    {
+        int a, b;
+        cin >> a >> b;
+        dist[a][b] = 1;
+    }
+
+    for (int k = 1; k <= n; ++k) 
+    {
+        for (int i = 1; i <= n; ++i) 
+        {
+            for (int j = 1; j <= n; ++j) 
+            {
+                dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
+            }
+        }
+    }
+
+    int ans = 0;
+  
+    for (int i = 1; i <= n; ++i) 
+    {
+        int cnt = 0;
+      
+        for (int j = 1; j <= n; ++j) 
+        {
+            if (dist[i][j] != INF || dist[j][i] != INF) {
+              cnt++;
+            }  
+        }
+      
+        if (cnt == n - 1) ans++;
+    }
+
+    cout << ans << "\n";
+
+    return 0;
+}
diff --git "a/13_\354\265\234\353\213\250\352\262\275\353\241\234/\355\225\251\354\212\271\355\203\235\354\213\234\354\232\224\352\270\210.cpp" "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/\355\225\251\354\212\271\355\203\235\354\213\234\354\232\224\352\270\210.cpp"
new file mode 100644
index 0000000..53408cd
--- /dev/null
+++ "b/13_\354\265\234\353\213\250\352\262\275\353\241\234/\355\225\251\354\212\271\355\203\235\354\213\234\354\232\224\352\270\210.cpp"
@@ -0,0 +1 @@
+//13_최단경로 도전 1번:합승택시요금.cpp