20240729 애쉬(박민아) - 2주차

boj/ashsty/week2/1461.java

@@ -0,0 +1,61 @@
+import java.util.*;
+import java.io.*;
+
+public class Main{
+
+    static int max=0;
+    static int n;
+    static int countPlus=0;
+    static int countMinus=0;
+    static int count = 0;
+    static List<Integer> plus;
+    static List<Integer> minus;
+
+    public static void main(String[] args) throws IOException{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        StringTokenizer str1 = new StringTokenizer(br.readLine());
+
+        int m = Integer.parseInt(str1.nextToken());
+        n = Integer.parseInt(str1.nextToken());
+
+        plus=new ArrayList<>();
+        minus=new ArrayList<>();
+
+        StringTokenizer str2 = new StringTokenizer(br.readLine());
+
+        for(int i=0; i<m; i++){
+            int num = Integer.parseInt(str2.nextToken());
+            max = Math.max(max, Math.abs(num));
+
+            if(num>=0){
+                plus.add(num);
+            }
+            else{
+                minus.add(Math.abs(num));
+            }
+        }
+
+        Collections.sort(plus);
+        Collections.sort(minus);
+
+        greedySejun(plus);
+        greedySejun(minus);
+
+        System.out.println(count - max);
+    }
+
+    private static void greedySejun(List<Integer> array){
+        int flag = array.size() % n;
+        int i = array.size() - 1;
+
+        while (i>flag-1){
+            count+=array.get(i)*2;
+            i-=n;
+        }
+
+        if(flag>0){
+            count+=array.get(i)*2;
+        }
+    }
+}

boj/ashsty/week2/1890.java

@@ -0,0 +1,49 @@
+import java.util.*;
+import java.io.*;
+
+public class Main{
+
+    static int max=0;
+    static int m;
+    static int n;
+    static int count = 0;
+    static int[][] map;
+    static long[][] check;
+
+    public static void main(String[] args) throws IOException{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        m = Integer.parseInt(br.readLine());
+
+        map = new int[m+1][m+1];
+        check = new long[m+1][m+1];
+
+        for(int i=1; i<=m; i++){
+            StringTokenizer str = new StringTokenizer(br.readLine());
+            for(int j=1; j<=m; j++){
+                map[i][j] = Integer.parseInt(str.nextToken());
+            }
+        }
+
+        check[1][1]=1;
+        dp(1, 1);
+
+        System.out.println(check[m][m]);
+    }
+
+    private static void dp(int startX, int startY){
+        int num=0;
+
+        for(int i=startX; i<=m;i++){
+            for(int j=startY; j<=m; j++){
+                num = map[i][j];
+                if(i+num<=m && num !=0){
+                    check[i+num][j] +=check[i][j];
+                }
+                if(j+num<=m && num !=0){
+                    check[i][j+num] +=check[i][j];
+                }
+            }
+        }
+    }
+}

boj/ashsty/week2/5567.java

@@ -0,0 +1,54 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        int n = Integer.parseInt(br.readLine()); // 총 동기의 수
+        int m = Integer.parseInt(br.readLine()); // 친구 관계의 수
+
+        // 친구 관계를 저장할 인접 리스트
+        List<List<Integer>> friends = new ArrayList<>();
+        for (int i = 0; i <= n; i++) {
+            friends.add(new ArrayList<>());
+        }
+
+        // 친구 관계 입력 받기
+        for (int i = 0; i < m; i++) {
+            st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+            friends.get(a).add(b);
+            friends.get(b).add(a);
+        }
+
+        // BFS를 위한 변수
+        boolean[] visited = new boolean[n + 1];
+        Queue<Integer> queue = new LinkedList<>();
+        int count = 0;
+        int level = 0;
+
+        // 상근이의 친구를 찾기 위한 BFS
+        visited[1] = true;
+        queue.add(1);
+
+        while (!queue.isEmpty() && level < 2) {
+            int size = queue.size();
+            for (int i = 0; i < size; i++) {
+                int current = queue.poll();
+                for (int friend : friends.get(current)) {
+                    if (!visited[friend]) {
+                        visited[friend] = true;
+                        queue.add(friend);
+                        count++;
+                    }
+                }
+            }
+            level++;
+        }
+
+        System.out.println(count);
+    }
+}