diff --git "a/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-18119] \353\213\250\354\226\264 \354\225\224\352\270\260.java" "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-18119] \353\213\250\354\226\264 \354\225\224\352\270\260.java"
new file mode 100644
index 00000000..31802bf9
--- /dev/null
+++ "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-18119] \353\213\250\354\226\264 \354\225\224\352\270\260.java"	
@@ -0,0 +1,51 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    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());
+
+        //단어 저장
+        List<Integer> words = new ArrayList<>();
+        for(int i=0; i<n; i++) {
+            String input = br.readLine();
+            int word = 0;
+            for(char c : input.toCharArray()) {
+                int offset = c - 'a';
+                int target = (1 << offset);
+                word = word | target;
+            }
+            words.add(word);
+        }
+
+        //현재 기억하는 알파벳 정보
+        int current = (1 << ('z'-'a') + 1) - 1;
+
+        StringBuilder sb = new StringBuilder();
+        for(int i=0; i<m; i++) {
+            String[] input = br.readLine().split(" ");
+
+            int offset = input[1].charAt(0) - 'a';
+            int target = (1 << offset);
+
+            //1이면 해당 알파벳을 잊어버림
+            if(input[0].equals("1")) current = current ^ target;
+                //0이면 다시 기억함
+            else current = current | target;
+
+            //모든 단어와 비교하여 해당 단어의 알파벳을 모두 기억하면 +1
+            int count = 0;
+            for(int word : words) {
+                if(word == (word & current)) count++;
+            }
+            sb.append(count).append("\n");
+        }
+
+        System.out.println(sb.toString().trim());
+    }
+}
diff --git "a/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-1911] \355\235\231\352\270\270 \353\263\264\354\210\230\355\225\230\352\270\260.java" "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-1911] \355\235\231\352\270\270 \353\263\264\354\210\230\355\225\230\352\270\260.java"
new file mode 100644
index 00000000..73697c05
--- /dev/null
+++ "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-1911] \355\235\231\352\270\270 \353\263\264\354\210\230\355\225\230\352\270\260.java"	
@@ -0,0 +1,37 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    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 l = Integer.parseInt(st.nextToken());
+
+        int[][] water = new int[n][2];
+        for(int i=0; i<n; i++) {
+            st = new StringTokenizer(br.readLine());
+            water[i][0] = Integer.parseInt(st.nextToken());
+            water[i][1] = Integer.parseInt(st.nextToken());
+        }
+
+        Arrays.sort(water, (o1, o2) -> Integer.compare(o1[0], o2[0]));
+
+        int result = 0;
+        int pre = 0;
+        for(int i=0; i<n; i++) {
+            //널빤지의 끝 위치와 웅덩이의 시작 위치 중 더 큰 값으로 설정
+            pre = Math.max(pre, water[i][0]);
+            //하나씩 놓기
+            while(pre < water[i][1]) {
+                result++;
+                pre += l;
+            }
+        }
+
+        System.out.println(result);
+    }
+}
diff --git "a/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-3020] \352\260\234\353\230\245\353\262\214\353\240\210.java" "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-3020] \352\260\234\353\230\245\353\262\214\353\240\210.java"
new file mode 100644
index 00000000..de8a1703
--- /dev/null
+++ "b/\354\234\240\353\263\221\352\267\234_15\354\243\274\354\260\250/[BOJ-3020] \352\260\234\353\230\245\353\262\214\353\240\210.java"	
@@ -0,0 +1,49 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        //입력 값 저장
+        int n = Integer.parseInt(st.nextToken());
+        int h = Integer.parseInt(st.nextToken());
+
+        int[] number = new int[n];
+        for(int i=0; i<n; i++) {
+            number[i] = Integer.parseInt(br.readLine());
+        }
+
+        //석순의 변화량을 체크
+        int[] count = new int[h];
+        for(int i=0; i<n; i+=2) {
+            count[0]++;
+            count[number[i]]--;
+        }
+
+        //종유석의 변화량을 체크
+        for(int i=1; i<n; i+=2) {
+            count[h-number[i]]++;
+        }
+
+        //누적합 배열 세팅
+        int[] sum = new int[h];
+        sum[0] = count[0];
+        for(int i=1; i<h; i++) {
+            sum[i] = sum[i-1]+count[i];
+        }
+
+        //가장 작은 값과 그 개수 구하기
+        Arrays.sort(sum);
+        int result = 1;
+        for(int i=1; i<h; i++) {
+            if(sum[0] != sum[i]) break;
+            result++;
+        }
+
+        System.out.println(sum[0]+" "+result);
+    }
+}