[Week08] BOJ 15989: 1, 2, 3 더하기 4

personal/JAEHEE25/BOJ/BOJ15988.java

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+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        //dp
+        long[] dp = new long[1000001];
+        dp[1] = 1;
+        dp[2] = 2;
+        dp[3] = 4;
+        for (int i = 4; i <= 1000000; i++) {
+            dp[i] = (dp[i - 3] + dp[i - 2] + dp[i - 1]) % 1_000_000_009;
+        }
+
+        //정답 출력
+        StringBuilder answer = new StringBuilder();
+        int T = Integer.parseInt(br.readLine());
+        for (int i = 0; i < T; i++) {
+            int t = Integer.parseInt(br.readLine());
+            answer.append(dp[t] % 1_000_000_009).append("\n");
+        }
+        System.out.println(answer);
+    }
+}

weekly/week08/BOJ_13549_숨바꼭질3/JAEHEE25.java

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+package week08.BOJ_13549_숨바꼭질3;
+
+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class BOJ13549 {
+    static boolean[] visit;
+    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()); //수빈
+        int K = Integer.parseInt(st.nextToken()); //동생
+
+        int answer = Integer.MAX_VALUE;
+        visit = new boolean[100001];
+        Queue<Pos> queue = new LinkedList<>();
+        queue.add(new Pos(N, 0));
+        while (!queue.isEmpty()) {
+            Pos poll = queue.poll();
+            visit[poll.x] = true;
+
+            if (poll.x == K) {
+                answer = Math.min(answer, poll.time);
+            }
+
+            if (check(poll.x + 1)) queue.add(new Pos(poll.x + 1, poll.time + 1));
+            if (check(poll.x - 1)) queue.add(new Pos(poll.x - 1, poll.time + 1));
+            if (check(poll.x * 2)) queue.add(new Pos(poll.x * 2, poll.time));
+        }
+        System.out.println(answer);
+    }
+
+    static boolean check(int value) {
+        return value >= 0 && value <= 100000 && !visit[value];
+    }
+}
+
+class Pos {
+    int x;
+    int time;
+
+    Pos(int x, int time) {
+        this.x = x;
+        this.time = time;
+    }
+}

weekly/week08/BOJ_15989_1,2,3더하기4/JAEHEE25.java

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+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class BOJ15989 {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        //dp[i][j] = i를 만들 때 마지막 숫자가 j이고, 오름차순인 방법의 수
+        int[][] dp = new int[10001][4];
+        dp[1][1] = 1; //1
+        dp[2][1] = 1; //1,1
+        dp[2][2] = 1; //2
+        dp[3][1] = 1; //1,1,1
+        dp[3][2] = 1; //1,2
+        dp[3][3] = 1; //3
+        for (int i = 4; i <= 10000; i++) {
+            dp[i][1] = dp[i-1][1];
+            dp[i][2] = dp[i-2][1] + dp[i-2][2];
+            dp[i][3] = dp[i-3][1] + dp[i-3][2] + dp[i-3][3];
+        }
+
+        //정답 출력
+        StringBuilder answer = new StringBuilder();
+        int T = Integer.parseInt(br.readLine());
+        for (int i = 0; i < T; i++) {
+            int t = Integer.parseInt(br.readLine());
+            answer.append(dp[t][1] + dp[t][2] + dp[t][3]).append("\n");
+        }
+        System.out.println(answer);
+    }
+}

weekly/week08/BOJ_2531_회전초밥/JAEHEE25.java

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+package week08.BOJ_2531_회전초밥;
+
+import java.util.*;
+import java.lang.*;
+import java.io.*;
+
+class BOJ2531 {
+    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 d = Integer.parseInt(st.nextToken());
+        int k = Integer.parseInt(st.nextToken());
+        int c = Integer.parseInt(st.nextToken());
+
+        int[] plates = new int[N];
+        for (int i = 0; i < N; i++) {
+            plates[i] = Integer.parseInt(br.readLine());
+        }
+
+        Map<Integer, Integer> sushi = new HashMap<>();
+        //처음 k개의 접시
+        for (int i = 0; i < k; i++) {
+            sushi.put(plates[i], sushi.getOrDefault(plates[i], 0) + 1);
+        }
+
+        int start = 0;
+        int end = k;
+        int answer = sushi.size();
+        if (!sushi.containsKey(c)) answer++;
+
+        while (start < N - 1) {
+            //이전 스시 빼기
+            if (sushi.get(plates[start]) == 1) { //1개 남았다면 아예 삭제
+                sushi.remove(plates[start]);
+            } else {
+                sushi.put(plates[start], sushi.get(plates[start]) - 1);
+            }
+
+            if (end >= N) end %= N; //원형 벨트
+            sushi.put(plates[end], sushi.getOrDefault(plates[end], 0) + 1); //다음 초밥 넣기
+
+            int cnt = sushi.size();
+            if (!sushi.containsKey(c)) {
+                cnt++;
+            }
+            answer = Math.max(answer, cnt);
+
+            start++;
+            end++;
+
+        }
+        System.out.println(answer);
+    }
+}