diff --git a/src/jinu/week21/Week21_18808.java b/src/jinu/week21/Week21_18808.java
new file mode 100644
index 0000000..9eb84c4
--- /dev/null
+++ b/src/jinu/week21/Week21_18808.java
@@ -0,0 +1,160 @@
+package jinu.week21;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringTokenizer;
+
+public class Week21_18808 {
+
+    static int noteBook[][];
+
+    static List<int[][]> stickers;
+
+    public static void main(String[] args) throws Exception {
+
+        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());
+
+        noteBook = new int[N][M];
+
+        int K = Integer.parseInt(st.nextToken());
+
+        stickers = new ArrayList<>();
+
+        for(int i = 0;i < K; i++){
+            st = new StringTokenizer(br.readLine());
+
+            int R = Integer.parseInt(st.nextToken());
+            int C = Integer.parseInt(st.nextToken());
+
+            int tmp[][] = new int[R][C];
+
+            for(int r = 0; r<R; r++){
+                st = new StringTokenizer(br.readLine());
+                for(int j = 0; j<C;j++){
+                    tmp[r][j] = Integer.parseInt(st.nextToken());
+                }
+            }
+
+            stickers.add(tmp);
+        }
+
+//        print(noteBook);
+//        System.out.println("---------------------");
+
+
+
+        for(int sticker[][] : stickers){
+
+            int applySticker[][] = sticker;
+
+            boolean next = false;
+
+            for(int k =0 ;k < 4; k++){
+
+                for(int i =0 ;i< N;i++){
+                    for(int j =0 ; j<M;j++){
+
+                        if(next){
+                            break;
+                        }
+
+                        if(canApply(noteBook, applySticker, i, j)){
+                            apply(noteBook, applySticker, i, j);
+                            next = true;
+                        }
+
+                    }
+                }
+
+                if(next){
+                    break;
+                }
+
+                applySticker = turnRight(applySticker);
+            }
+//            print(noteBook);
+//            System.out.println("---------------------------");
+        }
+
+        //  print(noteBook);
+
+        System.out.println(countOne(noteBook));
+
+
+
+
+    }
+
+    public static boolean canApply(int [][]noteBook, int applySticker[][], int i, int j){
+        for(int y = i; y < i + applySticker.length; y++){
+            for(int x = j; x < j + applySticker[0].length; x++){
+
+                if(y >= noteBook.length || x >= noteBook[0].length){
+                    return false;
+                }
+
+                if(noteBook[y][x]==1 && applySticker[y-i][x-j] == 1){
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    public static void apply(int [][]noteBook, int applySticker[][], int i, int j){
+
+        for(int y = i; y < i + applySticker.length; y++){
+            for(int x = j; x < j + applySticker[0].length; x++){
+
+                if(noteBook[y][x]==0 && applySticker[y-i][x-j]==1){
+                    noteBook[y][x] = applySticker[y-i][x-j];
+                }
+            }
+        }
+    }
+
+    public static int[][] turnRight(int [][]applySticker){
+
+        int tmpApplySticker[][] = new int[applySticker[0].length][applySticker.length];
+
+        for(int i = 0; i <applySticker.length; i++){
+            for(int j =0;j<applySticker[0].length; j++){
+                tmpApplySticker[j][applySticker.length-1-i] = applySticker[i][j];
+            }
+        }
+
+        return tmpApplySticker;
+    }
+
+    public static void print(int noteBook[][]){
+        for(int i=0;i<noteBook.length; i++){
+            for(int j=0;j<noteBook[0].length; j++){
+                System.out.print(noteBook[i][j]+" ");
+            }
+            System.out.println();
+        }
+    }
+
+    public static int countOne(int noteBook[][]){
+
+        int count = 0;
+
+        for(int i=0;i<noteBook.length; i++){
+            for(int j=0;j<noteBook[0].length; j++){
+                if(noteBook[i][j]==1){
+                    count++;
+                }
+            }
+        }
+
+        return count;
+    }
+
+}
diff --git a/src/jinu/week21/Week21_2461.java b/src/jinu/week21/Week21_2461.java
new file mode 100644
index 0000000..677be26
--- /dev/null
+++ b/src/jinu/week21/Week21_2461.java
@@ -0,0 +1,83 @@
+package jinu.week21;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class Week21_2461 {
+
+    static List<Integer> abilities[];
+
+    static class Node implements Comparable<Node>{
+        int index;
+        int ability;
+
+        public Node(int index, int ability){
+            this.index = index;
+            this.ability = ability;
+        }
+
+        public int compareTo(Node n){
+            return this.ability-n.ability;
+        }
+    }
+    public static void main(String[] args) throws Exception {
+
+        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());
+
+        abilities = new List[N];
+        for(int i =0;i<N;i++){
+            st = new StringTokenizer(br.readLine());
+            abilities[i] = new ArrayList<>();
+            for(int j=0;j<M;j++){
+                abilities[i].add(Integer.parseInt(st.nextToken()));
+            }
+            Collections.sort(abilities[i]);
+        }
+
+        int []abilityIndex = new int[N];
+
+        Arrays.fill(abilityIndex, 0);
+
+        PriorityQueue<Node> pq = new PriorityQueue<>();
+
+        int max = Integer.MIN_VALUE;
+
+        for(int i=0;i<N;i++){
+            pq.add(new Node(i, abilities[i].get(abilityIndex[i])));
+            max = Math.max(max, abilities[i].get(abilityIndex[i]));
+        }
+
+        int minDiff = Integer.MAX_VALUE;
+
+        while(!pq.isEmpty()){
+
+            Node n = pq.poll();
+            minDiff = Math.min(minDiff, (max-n.ability));
+
+//            System.out.println("max: "+max);
+//            System.out.println("min: "+n.ability);
+
+            if(abilityIndex[n.index]<=M-2){
+                abilityIndex[n.index]++;
+                max = Math.max(max, abilities[n.index].get(abilityIndex[n.index]));
+                pq.add(new Node(n.index, abilities[n.index].get(abilityIndex[n.index])));
+            }
+            else{
+                break;
+            }
+        }
+
+        System.out.println(minDiff);
+    }
+
+}
diff --git a/src/jinu/week21/Week21_2515.java b/src/jinu/week21/Week21_2515.java
new file mode 100644
index 0000000..f044314
--- /dev/null
+++ b/src/jinu/week21/Week21_2515.java
@@ -0,0 +1,90 @@
+package jinu.week21;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class Week21_2515 {
+
+    static class Painting implements Comparable<Painting>{
+
+        int height;
+        int cost;
+
+        public Painting(int height, int cost){
+            this.height = height;
+            this.cost = cost;
+        }
+
+        @Override
+        public int compareTo(Painting p){
+            return this.height - p.height;
+        }
+    }
+
+    static Painting[] paintings;
+    static int []limit, dp;
+    static int N,S;
+
+    public static void main(String[] args) throws Exception {
+
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        N = Integer.parseInt(st.nextToken());
+        S = Integer.parseInt(st.nextToken());
+
+        paintings = new Painting[N];
+        dp = new int[N];
+        limit = new int[N];
+
+        for(int i=0;i<N;i++){
+            st = new StringTokenizer(br.readLine());
+            paintings[i] = new Painting(Integer.parseInt(st.nextToken()), Integer.parseInt(st.nextToken()));
+        }
+
+        Arrays.sort(paintings);
+
+        dp[0] = paintings[0].cost;
+
+        for(int i=1;i<N;i++){
+            int findMaxHighIndex = binarySearch(i);
+            if(findMaxHighIndex > -1){
+                dp[i] = Math.max(dp[findMaxHighIndex]+paintings[i].cost, dp[i-1]);
+            }
+            else{
+                dp[i] = Math.max(dp[i-1], paintings[i].cost);
+            }
+        }
+
+        System.out.println(dp[N-1]);
+
+
+
+
+
+    }
+
+    static int binarySearch(int index){
+        int mid = 0;
+        int left = 0;
+        int right = index;
+
+        while(left<=right){
+            mid = (left+right)/2;
+
+            int diff = paintings[index].height - paintings[mid].height;
+
+            if(diff>=S){
+                left = mid+1;
+            }
+            else{
+                right = mid - 1;
+            }
+        }
+
+        return left - 1;
+    }
+
+}