diff --git "a/4\354\243\274\354\260\250/\352\260\200\354\236\245\355\201\260\354\210\230/\352\260\200\354\236\245\355\201\260\354\210\230_\354\235\264\354\243\274\355\230\201.java" "b/4\354\243\274\354\260\250/\352\260\200\354\236\245\355\201\260\354\210\230/\352\260\200\354\236\245\355\201\260\354\210\230_\354\235\264\354\243\274\355\230\201.java"
new file mode 100644
index 0000000..fb99641
--- /dev/null
+++ "b/4\354\243\274\354\260\250/\352\260\200\354\236\245\355\201\260\354\210\230/\352\260\200\354\236\245\355\201\260\354\210\230_\354\235\264\354\243\274\355\230\201.java"
@@ -0,0 +1,39 @@
+/*
+어떤 것 먼저?
+
+*/
+import java.util.*;
+class Solution {
+    public static class StringNum implements Comparable<StringNum> {
+        
+        String num;
+        
+        public StringNum(String num){
+            this.num = num;
+        }
+        
+        @Override
+        public int compareTo(StringNum o1){
+            return -1 * (this.num + o1.num).compareTo(o1.num + this.num);
+        }
+        
+    }
+
+    public String solution(int[] numbers) {
+        String answer = "";
+        
+        StringNum[] nums = new StringNum[numbers.length];
+        
+        for(int i = 0; i < nums.length; i++) {
+            nums[i] = new StringNum(String.valueOf(numbers[i]));
+        }
+        
+        Arrays.sort(nums);
+        
+        if(nums[0].num.equals("0")) return "0";
+
+        for(int i=0; i<nums.length; i++) answer += nums[i].num;
+        
+        return answer;
+    }
+}
\ No newline at end of file
diff --git "a/4\354\243\274\354\260\250/\353\221\220\353\217\231\354\240\204/\353\221\220\353\217\231\354\240\204_\354\235\264\354\243\274\355\230\201.java" "b/4\354\243\274\354\260\250/\353\221\220\353\217\231\354\240\204/\353\221\220\353\217\231\354\240\204_\354\235\264\354\243\274\355\230\201.java"
new file mode 100644
index 0000000..90f1318
--- /dev/null
+++ "b/4\354\243\274\354\260\250/\353\221\220\353\217\231\354\240\204/\353\221\220\353\217\231\354\240\204_\354\235\264\354\243\274\355\230\201.java"
@@ -0,0 +1,130 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayDeque;
+import java.util.Arrays;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+/**
+ * 시작 시간: 오후 9시 54분
+ * 
+ * 문제 해섞)
+ * - N*M 보드와 4개의 버튼
+ * - 각각의 칸은 비어있거나, 벽
+ * - 두 개의 빈칸에는 동전이 하나씩 놓여있다
+ * - 버튼은 위, 오, 왼, 아
+ * - 버튼을 누르면 두 동전이 동시에 이동한다
+ * 		- 이동하려는 칸이 벽이면, 이동하지 않는다
+ * 		- 칸이 없으면, 보드 바깥으로 떨어진다
+ * 		- 그 외에는 한칸 이동한다. 이동하려는 칸에 동전이 있는 경우에도 한칸 이동한다.
+ * 
+ * 두 동전 중 하나만 보드엣 ㅓ떨어뜨리기 위해 버튼을 쵯 ㅗ몇번 눌러야하는지 구행햐ㅏㄴ다.
+ * 첫째 줄에 두 동전 중 하나만 보드에서 떨어뜨리기 위해 눌러야 하는 버튼의 최소 횟수를 출력한다. 
+ * 만약, 두 동전을 떨어뜨릴 수 없거나, 버튼을 10번보다 많이 눌러야 한다면, -1을 출력한다.
+ * 
+ * 
+ * @author GODJUHYEOK
+ *
+ */
+public class Main {
+
+	private static class Coin {
+		
+		int r;
+		int c;
+		
+		public Coin(int r, int c) {	
+			this.r = r;
+			this.c = c;
+		}
+		
+	}
+	
+	private static int N, M;
+	private static int[][] deltas = {{1, 0}, {-1, 0}, {0, -1}, {0, 1}};
+	private static boolean[][][][] visited;
+	private static char[][] map;
+	
+	public static void main(String[] args) throws IOException { 
+		
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		
+		map = new char[N][M];
+		visited = new boolean[N][M][N][M];
+		
+		Coin[] arr = {null, null};
+		
+		
+		for(int i=0, idx=0; i<N; i++) {
+			map[i] = br.readLine().toCharArray();
+			for(int j=0; j<M; j++) {
+				if(map[i][j] == 'o') {
+					arr[idx++] = new Coin(i, j);
+				}
+			}
+		}
+		
+		System.out.println(gameBFS(arr));
+		
+	}
+
+	private static int gameBFS(Coin[] arr) {
+		
+		Queue<Coin[]> q = new ArrayDeque<Coin[]>();
+		visited[arr[0].r][arr[0].c][arr[1].r][arr[1].c] = true;
+		q.offer(arr);
+		
+		int turn = 0;
+		while(turn < 10 && !q.isEmpty()) {
+			
+			int qSize = q.size();
+			turn++;
+			for (int k=0; k<qSize; k++) {
+				Coin[] temp = q.poll();
+				for(int[] d : deltas) {	
+					
+					int nr1 = temp[0].r + d[0];
+					int nc1 = temp[0].c + d[1];
+					
+					int nr2 = temp[1].r + d[0];
+					int nc2 = temp[1].c + d[1];
+					
+					if(isOutOfRange(nr1, nc1) && isOutOfRange(nr2, nc2)) continue;
+					else if(isOutOfRange(nr1, nc1) || isOutOfRange(nr2, nc2)) {
+						return turn;
+					}
+					
+					if(visited[nr1][nc1][nr2][nc2]) continue;
+					
+					visited[nr1][nc1][nr2][nc2] = true;
+					
+					if(map[nr1][nc1] == '#') {
+						nr1 = temp[0].r;
+						nc1 = temp[0].c;
+					}
+					
+					if(map[nr2][nc2] == '#') {
+						nr2 = temp[1].r;
+						nc2 = temp[1].c;
+					}
+					
+					q.offer(new Coin[] {new Coin(nr1, nc1), new Coin(nr2, nc2)});
+					
+				}
+			}
+		}
+		
+		return -1;
+		
+	}
+
+	private static boolean isOutOfRange(int r, int c) {
+		return r < 0 || c < 0 || r>=N || c>=M;
+	}
+	
+}
diff --git "a/4\354\243\274\354\260\250/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234_\354\235\264\354\243\274\355\230\201.java" "b/4\354\243\274\354\260\250/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234_\354\235\264\354\243\274\355\230\201.java"
new file mode 100644
index 0000000..80a51de
--- /dev/null
+++ "b/4\354\243\274\354\260\250/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234/\355\225\251\353\246\254\354\240\201\354\235\270\354\235\264\353\217\231\352\262\275\353\241\234_\354\235\264\354\243\274\355\230\201.java"
@@ -0,0 +1,68 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+    static final int MAX = 1001;
+    static final int INF = Integer.MAX_VALUE;
+    static ArrayList<Pair>[] adj = new ArrayList[MAX];
+    static int[] dist = new int[MAX];
+    static int[] dp = new int[MAX];
+
+    static class Pair implements Comparable<Pair> {
+        int cost, vertex;
+        public Pair(int cost, int vertex) {
+            this.cost = cost;
+            this.vertex = vertex;
+        }
+        public int compareTo(Pair other) {
+            return Integer.compare(this.cost, other.cost);
+        }
+    }
+
+    public static void dijkstra(int start) {
+        Arrays.fill(dist, INF);
+        PriorityQueue<Pair> pq = new PriorityQueue<>();
+        dist[start] = 0;
+        pq.add(new Pair(0, start));
+        while (!pq.isEmpty()) {
+            Pair top = pq.poll();
+            int curCost = top.cost;
+            int cur = top.vertex;
+            if (dist[cur] != curCost) continue;
+            for (Pair edge : adj[cur]) {
+                int nextCost = edge.cost;
+                int next = edge.vertex;
+                if (dist[next] > curCost + nextCost) {
+                    dist[next] = curCost + nextCost;
+                    pq.add(new Pair(dist[next], next));
+                }
+                if (dist[cur] > dist[next]) {
+                    dp[cur] += dp[next];
+                }
+            }
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int n = Integer.parseInt(st.nextToken());
+        int m = Integer.parseInt(st.nextToken());
+        for (int i = 0; i < MAX; i++) {
+            adj[i] = new ArrayList<>();
+        }
+        dp[2] = 1;
+        while (m-- > 0) {
+        	st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+            int c = Integer.parseInt(st.nextToken());
+            adj[a].add(new Pair(c, b));
+            adj[b].add(new Pair(c, a));
+        }
+        dijkstra(2);
+        System.out.println(dp[1]);
+    }
+}