Merge pull request #206 from JavaCote/sangeok

leesangeok · web-flow · commit 4e795e346f65 · 2026-01-09T09:35:44.000+09:00
이상억 36주차
diff --git a/week36/이상억/backjoon/도영이가_만든_맛있는_음식.java b/week36/이상억/backjoon/도영이가_만든_맛있는_음식.java
@@ -0,0 +1,47 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int N;
+    static int[] S, B;
+    static int answer = Integer.MAX_VALUE;
+
+    static void dfs(int idx, long sour, long bitter, boolean used) {
+        if (idx == N) {
+            if (used) {
+                answer = Math.min(answer, (int)Math.abs(sour - bitter));
+            }
+            return;
+        }
+
+        // 현재 재료 사용
+        dfs(idx + 1,
+                sour * S[idx],
+                bitter + B[idx],
+                true);
+
+        // 현재 재료 사용 안 함
+        dfs(idx + 1,
+                sour,
+                bitter,
+                used);
+    }
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+
+        S = new int[N];
+        B = new int[N];
+
+        for (int i = 0; i < N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            S[i] = Integer.parseInt(st.nextToken());
+            B[i] = Integer.parseInt(st.nextToken());
+        }
+
+        dfs(0, 1, 0, false);
+        System.out.println(answer);
+    }
+}
diff --git a/week36/이상억/backjoon/비밀_모임.java b/week36/이상억/backjoon/비밀_모임.java
@@ -0,0 +1,104 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static class Edge {
+        int to;
+        int cost;
+        Edge(int to, int cost) {
+            this.to = to;
+            this.cost = cost;
+        }
+    }
+
+    static List<Edge>[] graph;
+    static int N;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        int T = Integer.parseInt(br.readLine());
+
+        for (int tc = 0; tc < T; tc++) {
+
+            st = new StringTokenizer(br.readLine());
+            N = Integer.parseInt(st.nextToken());
+            int M = Integer.parseInt(st.nextToken());
+
+            graph = new ArrayList[N + 1];
+            for (int i = 1; i <= N; i++) {
+                graph[i] = new ArrayList<>();
+            }
+
+            for (int i = 0; i < M; i++) {
+                st = new StringTokenizer(br.readLine());
+                int a = Integer.parseInt(st.nextToken());
+                int b = Integer.parseInt(st.nextToken());
+                int c = Integer.parseInt(st.nextToken());
+
+                graph[a].add(new Edge(b, c));
+                graph[b].add(new Edge(a, c));
+            }
+
+            int K = Integer.parseInt(br.readLine());
+            st = new StringTokenizer(br.readLine());
+
+            int[] friends = new int[K];
+            for (int i = 0; i < K; i++) {
+                friends[i] = Integer.parseInt(st.nextToken());
+            }
+
+            int[] sum = new int[N + 1];
+
+            for(int f : friends){
+                int[] dist = dijkstra(f);
+                for(int i = 1; i <= N; i++){
+                    sum[i] += dist[i];
+                }
+            }
+
+            int answer = 1;
+            int min = sum[1];
+            for(int i = 2; i <= N; i++){
+                if(sum[i] < min ){
+                    min = sum[i];
+                    answer = i;
+                }
+            }
+
+            System.out.println(answer);
+        }
+    }
+
+    static int[] dijkstra(int start) {
+        int[] dist = new int[N + 1];
+        Arrays.fill(dist, Integer.MAX_VALUE);
+        dist[start] = 0;
+
+        PriorityQueue<int[]> pq =
+                new PriorityQueue<>((a, b) -> Integer.compare(a[1], b[1]));
+
+        pq.add(new int[]{start, 0});
+
+        while (!pq.isEmpty()) {
+            int[] cur = pq.poll();
+            int now = cur[0];
+            int cost = cur[1];
+
+            if (cost > dist[now]) continue;
+
+            for (Edge e : graph[now]) {
+                int next = e.to;
+                int nextCost = cost + e.cost;
+
+                if (nextCost < dist[next]) {
+                    dist[next] = nextCost;
+                    pq.add(new int[]{next, nextCost});
+                }
+            }
+        }
+        return dist;
+    }
+}
diff --git a/week36/이상억/backjoon/여행_가자.java b/week36/이상억/backjoon/여행_가자.java
@@ -0,0 +1,54 @@
+import java.io.*;
+import java.util.*;
+
+
+public class Main{
+
+   static int[] parent;
+
+   static int find(int x){
+       if(parent[x] == x) return x;
+       return parent[x] = find(parent[x]);
+   }
+
+    static void union(int a, int b){
+        a = find(a);
+        b = find(b);
+        if (a != b) parent[b] = a;
+    }
+
+
+    public static void main(String[] args) throws IOException{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        int N = Integer.parseInt(br.readLine());
+        int M = Integer.parseInt(br.readLine());
+
+        parent = new int[N + 1];
+        for(int i = 1; i <= N; i++) parent[i] = i;
+
+        for(int i = 1; i <= N; i ++){
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for(int j = 1; j <= N; j++){
+                int connected  = Integer.parseInt(st.nextToken());
+                if(connected == 1){
+                    union(i,j);
+                }
+            }
+        }
+
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int first_city = Integer.parseInt(st.nextToken());
+        int root = find(first_city);
+
+        while(st.hasMoreTokens()){
+            int city = Integer.parseInt(st.nextToken());
+            if(find(city) != root){
+                System.out.println("NO");
+                return;
+            }
+        }
+
+        System.out.println("YES");
+    }
+}
diff --git a/week36/이상억/backjoon/출석체크.java b/week36/이상억/backjoon/출석체크.java
@@ -0,0 +1,51 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        st = new StringTokenizer(br.readLine());
+        int N = Integer.parseInt(st.nextToken());
+        int K = Integer.parseInt(st.nextToken());
+        int Q = Integer.parseInt(st.nextToken());
+        int M = Integer.parseInt(st.nextToken());
+
+        boolean[] sleep = new boolean[N + 3];   // 졸고 있는 학생
+        boolean[] attend = new boolean[N + 3];  // 출석한 학생
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < K; i++) {
+            sleep[Integer.parseInt(st.nextToken())] = true;
+        }
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < Q; i++) {
+            int x = Integer.parseInt(st.nextToken());
+            if (sleep[x]) continue; // 졸고 있으면 전파 X
+
+            for (int j = x; j <= N + 2; j += x) {
+                if (!sleep[j]) {
+                    attend[j] = true;
+                }
+            }
+        }
+
+        int[] prefix = new int[N + 3];
+        for (int i = 3; i <= N + 2; i++) {
+            prefix[i] = prefix[i - 1] + (attend[i] ? 0 : 1);
+        }
+
+        StringBuilder sb = new StringBuilder();
+
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int S = Integer.parseInt(st.nextToken());
+            int E = Integer.parseInt(st.nextToken());
+            sb.append(prefix[E] - prefix[S - 1]).append('\n');
+        }
+
+        System.out.print(sb);
+    }
+}
