diff --git a/seoul_15_suminkim/SWEA/Solution_d5_1248.java b/seoul_15_suminkim/SWEA/Solution_d5_1248.java
new file mode 100644
index 0000000..198c7c5
--- /dev/null
+++ b/seoul_15_suminkim/SWEA/Solution_d5_1248.java
@@ -0,0 +1,116 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.StringTokenizer;
+
+public class Solution_d5_1248 {
+	
+	static int v;
+	static List<Integer>[] adj;
+	static int[][] sTable;
+	static int[] depth;
+	static int[] subTree;
+	static int k;
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		int tc = Integer.parseInt(br.readLine());
+		StringBuilder sb = new StringBuilder();
+		for (int t = 1; t <= tc; t++) {
+			StringTokenizer st = new StringTokenizer(br.readLine());
+			v = Integer.parseInt(st.nextToken());
+			k = 32 - Integer.numberOfLeadingZeros(v);
+			int e = Integer.parseInt(st.nextToken());
+			int v1 = Integer.parseInt(st.nextToken());
+			int v2 = Integer.parseInt(st.nextToken());
+			setGraph(br.readLine(), e);
+			setParent();
+			setSTable();
+			setSubTree();
+			int lca = lca(v1, v2);
+			sb.append("#" + t + " " + lca + " " + subTree[lca] + "\n");
+		}
+		System.out.println(sb);
+	}
+
+	private static void setGraph(String readLine, int e) {
+		StringTokenizer st = new StringTokenizer(readLine);
+		adj = new List[v + 1];
+		for (int i = 1; i <= v; i++) {
+			adj[i] = new LinkedList<>();
+		}
+		for (int i = 0; i < e; i++) {
+			int v1 = Integer.parseInt(st.nextToken());
+			int v2 = Integer.parseInt(st.nextToken());
+			adj[v1].add(v2);
+			adj[v2].add(v1);
+		}
+	}
+	
+	private static void setParent() {
+		sTable = new int[v + 1][k];
+		depth = new int[v + 1];
+		sTable[1][0] = 1;
+		setParent(1);
+	}
+	
+	private static void setParent(int root) {
+		for (int child : adj[root]) {
+			if (sTable[child][0] > 0) continue;
+			sTable[child][0] = root;
+			depth[child] = depth[root] + 1;
+			setParent(child);
+		}
+	}
+	
+	private static void setSTable() {
+		for (int d = 1; d < k; d++) {
+			for (int i = 1; i <= v; i++) {
+				sTable[i][d] = sTable[sTable[i][d - 1]][d - 1];
+			}
+		}
+	}
+	
+	private static void setSubTree() {
+		subTree = new int[v + 1];
+		setSubTree(1);
+	}
+	
+	private static int setSubTree(int root) {
+		if (subTree[root] != 0) return subTree[root];
+		subTree[root] = 1;
+		for (int child : adj[root]) {
+			if (sTable[child][0] != root) continue;
+			subTree[root] += setSubTree(child);
+		}
+		return subTree[root];
+	}
+	
+	private static int lca(int v1, int v2) {
+		// v1이 더 깊은쪽이 되도록 변환
+		if (depth[v1] < depth[v2]) {
+			int temp = v1;
+			v1 = v2;
+			v2 = temp;
+		}
+		// v1, v2 depth 맞추기
+		for (int i = k - 1; i >= 0; i--) {
+			if (depth[v1] - depth[v2] >= (1 << i)) {
+				v1 = sTable[v1][i];
+			}
+		}
+		// 같아지면 같아진값 반환
+		if (v1 == v2) return v1;
+		// 공통 조상 찾기 : 가장 위쪽의 서로 다른 조상
+		for (int i = k - 1; i >= 0; i--) {
+			if (sTable[v1][i] != sTable[v2][i]) {
+				v1 = sTable[v1][i];
+				v2 = sTable[v2][i];
+			}
+		}
+		return sTable[v1][0];
+	}
+
+}