[김동-2학기 1주차 알고리즘 스터디]

김동하/2학기/[Baekjoon-10159] 저울.java

@@ -0,0 +1,71 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    public static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    public static StringBuilder sb = new StringBuilder();
+
+    public static int n,m;
+
+    public static List<Integer>[] arr;
+    public static List<Integer>[] rev;
+
+    public static void init() throws IOException {
+        n = Integer.parseInt(br.readLine());
+        m = Integer.parseInt(br.readLine());
+
+        arr = new ArrayList[n + 1];
+        rev = new ArrayList[n + 1];
+
+        for (int i = 1; i <= n; i++) {
+            arr[i] = new ArrayList<>();
+            rev[i] = new ArrayList<>();
+        }
+        for(int i = 0; i < m; i++) {
+            int a,b;
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            a = Integer.parseInt(st.nextToken());
+            b = Integer.parseInt(st.nextToken());
+            arr[a].add(b);
+            rev[b].add(a);
+        }
+    }
+
+    public static int bfs(int x, List<Integer>[] list){
+        Queue<Integer> q = new ArrayDeque<>();
+        q.add(x);
+        boolean[] visited = new boolean[n + 1];
+        visited[x] = true;
+        int cnt = 0;
+        while(!q.isEmpty()){
+            int cur = q.poll();
+            visited[cur] = true;
+            for(int next : list[cur]) {
+                if(!visited[next]){
+                    q.add(next);
+                    visited[next] = true;
+                    cnt++;
+                }
+            }
+        }
+        return cnt;
+    }
+
+    public static void solution() throws IOException {
+        init();
+        for(int i = 1; i <= n; i++){
+            sb.append(n - 1 - bfs(i,arr) - bfs(i, rev)).append("\n");
+        }
+
+    }
+
+    public static void main(String[] args)throws IOException {
+        solution();
+
+        bw.write(sb.toString());
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}

김동하/2학기/[Baekjoon-1561] 놀이 공원.java

@@ -0,0 +1,71 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    public static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    public static StringBuilder sb = new StringBuilder();
+
+    public static int n,m;
+    public static int[] arr;
+
+
+    public static void init() throws IOException {
+        StringTokenizer stk =  new StringTokenizer(br.readLine());
+        n = Integer.parseInt(stk.nextToken());
+        m = Integer.parseInt(stk.nextToken());
+        arr = new int[m + 1];
+        stk = new StringTokenizer(br.readLine());
+        for (int i = 1; i <= m; i++) {
+            arr[i] = Integer.parseInt(stk.nextToken());
+        }
+    }
+
+    public static long binarySearch() {
+        long st = 0;
+        long ed = 60000000000L;
+        while (st <= ed) {
+            long mid = (st + ed) / 2;
+            long sum = m;
+            for(int i = 1; i <= m; i++) {
+                sum += mid / arr[i];
+            }
+            if(sum < n) {
+                st = mid + 1;
+            }
+            else {
+                ed = mid - 1;
+            }
+        }
+        return st;
+    }
+
+    public static void solution() throws IOException {
+        init();
+        if(n <= m) sb.append(n).append("\n");
+        else {
+            long time = binarySearch();
+            long sum = m;
+            for(int i = 1; i <= m; i++) {
+                sum += (time - 1) / arr[i];
+            }
+
+            for(int i = 1; i <= m; i++) {
+                if(time % arr[i] == 0) sum++;
+                if(sum == n) {
+                    sb.append(i).append("\n");
+                    return;
+                }
+            }
+        }
+    }
+
+    public static void main(String[] args)throws IOException {
+        solution();
+
+        bw.write(sb.toString());
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}

김동하/2학기/[Baekjoon-17390] 이건꼭풀어야해.java

@@ -0,0 +1,49 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    public static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    public static StringBuilder sb = new StringBuilder();
+
+    public static int n,q;
+    public static int[] arr;
+    public static int[] sum;
+
+    public static void init() throws IOException {
+        StringTokenizer stk =  new StringTokenizer(br.readLine());
+        n = Integer.parseInt(stk.nextToken());
+        q = Integer.parseInt(stk.nextToken());
+        arr = new int[n];
+        sum = new int[n];
+        stk = new StringTokenizer(br.readLine());
+        for(int i = 0; i < n; i++){
+            arr[i] = Integer.parseInt(stk.nextToken());
+        }
+        Arrays.sort(arr);
+        sum[0] = arr[0];
+        for(int i = 1; i < n; i++){
+            sum[i] = sum[i-1] + arr[i];
+        }
+        for(int i = 0; i < q; i++) {
+            int a,b;
+            stk = new StringTokenizer(br.readLine());
+            a = Integer.parseInt(stk.nextToken()) - 1;
+            b = Integer.parseInt(stk.nextToken()) - 1;
+            sb.append(sum[b] - sum[a] + arr[a]).append('\n');
+        }
+    }
+
+    public static void solution() throws IOException {
+        init();
+    }
+
+    public static void main(String[] args)throws IOException {
+        solution();
+
+        bw.write(sb.toString());
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}

김동하/2학기/[Baekjoon-9935] 문자열 폭발.java

@@ -0,0 +1,65 @@
+import java.io.*;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringTokenizer;
+
+public class Main {
+    public static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    public static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    public static StringBuilder sb = new StringBuilder();
+
+    public static String str;
+    public static String word;
+
+    public static List<Character> stack = new ArrayList<>();
+
+
+    public static void init() throws IOException {
+        str = br.readLine();
+        word = br.readLine();
+    }
+
+    public static void solution() throws IOException {
+        init();
+        int len = str.length();
+        char ed = word.charAt(word.length() - 1);
+        for (int i = 0; i < len; i++) {
+            stack.add(str.charAt(i));
+            if (str.charAt(i) == ed) {
+                boolean flag = true;
+                int idx = word.length() - 1;
+                if(stack.size() < word.length()) continue;
+                for(int j = stack.size() - 1; j >= stack.size() - word.length(); j--) {
+                    if(stack.get(j) != word.charAt(idx)) {
+                        flag = false;
+                        break;
+                    }
+                    idx--;
+                }
+                if(flag) {
+                    int x = stack.size() - 1;
+                    for(int j = x; j >= x - word.length() + 1; j--) {
+                        stack.remove(j);
+                    }
+                }
+            }
+        }
+        if(stack.isEmpty()) {
+            sb.append("FRULA");
+            return;
+        }
+        for(int i = 0; i < stack.size(); i++) {
+            sb.append(stack.get(i));
+        }
+    }
+
+    public static void main(String[] args)throws IOException {
+        solution();
+
+        bw.write(sb.toString());
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+}