39_pushedrumex (#157)

* 크기가 작은 부분 문자열

* 미로 탈출 명령어

* 압축

* 거스름돈

* 우박 수열 정적분

week-39/pushedrumex/거스름돈.java

@@ -0,0 +1,16 @@
+import java.util.*;
+
+class Solution {
+    public int solution(int n, int[] money) {
+        int[] count = new int[n+1];
+        count[0] = 1;
+        for (int m: money) {
+            for (int value=0;value<n;value++) {
+                if (value+m > n) break;
+                count[value+m] += count[value];
+            }
+        }
+
+        return count[n] % 1_000_000_007;
+    }
+}

week-39/pushedrumex/미로 탈출 명령어.java

@@ -0,0 +1,89 @@
+import java.util.*;
+
+class Solution {
+
+    int n, m, r, c, k;
+    String answer = "impossible";
+    ArrayDeque<String> path = new ArrayDeque<>();
+    int count = 0;;
+
+    Direction[] directions = {
+        new Direction("d", 1, 0),
+        new Direction("l", 0, -1),
+        new Direction("r", 0, 1),
+        new Direction("u", -1, 0)
+    };
+
+    public String solution(int n, int m, int x, int y, int r, int c, int k) {
+        x--;
+        y--;
+        r--;
+        c--;
+        this.n = n;
+        this.m = m;
+        this.r = r;
+        this.c = c;
+        this.k = k;
+
+        dfs(new Node(x, y));
+
+        return answer;
+    }
+
+    void dfs(Node now) {
+
+        if (!answer.equals("impossible")) {
+            return;
+        }
+
+        if (Math.abs(now.x-r) + Math.abs(now.y-c) > k-count) {
+            return;
+        }
+
+        if ((Math.abs(now.x-r) + Math.abs(now.y-c) + k-count) % 2 != 0) {
+            return;
+        }
+
+        if (count == k) {
+            if (now.x == r && now.y == c) {
+                answer = String.join("", path);
+            }
+            return;
+        }
+
+        for (Direction direction: directions) {
+            int nextX = now.x + direction.dx;
+            int nextY = now.y + direction.dy;
+
+            if (nextX < 0 || nextX >= n || nextY < 0 || nextY >= m) {
+                continue;
+            }
+
+            count++;
+            path.addLast(direction.name);
+            dfs(new Node(nextX, nextY));
+            count--;
+            path.removeLast();
+        }
+    }
+
+    class Node {
+        int x;
+        int y;
+        Node(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    class Direction {
+        String name;
+        int dx;
+        int dy;
+        Direction(String name, int dx, int dy) {
+            this.name = name;
+            this.dx = dx;
+            this.dy = dy;
+        }
+    }
+}

week-39/pushedrumex/압축.java

@@ -0,0 +1,36 @@
+import java.util.*;
+
+class Solution {
+    public int[] solution(String msg) {
+        HashMap<String, Integer> map = new HashMap<>();
+        String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+        int idx = 1;
+        for (int i=0;i<26;i++) {
+            map.put(alpha.substring(i, i+1), idx++);
+        }
+
+        ArrayList<Integer> answer = new ArrayList<>();
+        int i = 0;
+        int N = msg.length();
+        while (i < N) {
+            String word = msg.substring(i, i+1);
+            i++;
+
+            // 사전에 없는 단어가 나올 때까지
+            while (i < N && map.containsKey(word)) {
+                word += msg.substring(i, i+1);
+                i++;
+            }
+
+            // 사전에 존재하지 않는다면
+            if (!map.containsKey(word)) {
+                answer.add(map.get(word.substring(0, word.length()-1)));
+                map.put(word, idx++);
+                i--;
+            } else {
+                answer.add(map.get(word));
+            }
+        }
+        return answer.stream().mapToInt(x -> x).toArray();
+    }
+}

week-39/pushedrumex/우박 수열 정적분.java

@@ -0,0 +1,41 @@
+import java.util.*;
+
+class Solution {
+    public double[] solution(int k, int[][] ranges) {
+        ArrayList<Integer> y = new ArrayList<>();
+        y.add(k);
+        while (k != 1) {
+            if (k % 2 == 0) {
+                k /= 2;
+            } else {
+                k = k * 3 + 1;
+            }
+            y.add(k);
+        }
+
+        double[] sums = new double[y.size()];
+        for (int i=0;i<y.size()-1;i++) {
+            sums[i+1] = (y.get(i)+y.get(i+1)) / (double)2;
+        }
+        for (int i=1;i<sums.length;i++) {
+            sums[i] += sums[i-1];
+        }
+        System.out.println(Arrays.toString(sums));
+        double[] answer = new double[ranges.length];
+        for (int i=0;i<ranges.length;i++) {
+            int[] range = ranges[i];
+            int x1 = range[0];
+            int x2 = sums.length+range[1]-1;
+
+            if (x1 > x2) {
+                answer[i] = -1;
+            } else if (x1 == x2) {
+                answer[i] = 0;
+            } else {
+                answer[i] = sums[x2] - sums[x1];
+            }
+        }
+
+        return answer;
+    }
+}

week-39/pushedrumex/크기가 작은 부분 문자열.java

@@ -0,0 +1,15 @@
+class Solution {
+    public int solution(String t, String p) {
+        int N = t.length();
+        int M = p.length();
+
+        long pLong = Long.parseLong(p);
+        int answer = 0;
+        for (int i=0;i<=N-M;i++) {
+            if (Long.parseLong(t.substring(i, i+M)) <= pLong) {
+                answer++;
+            }
+        }
+        return answer;
+    }
+}