8-kokeunho

kokeunho/README.md

@@ -9,4 +9,5 @@
 | 5차시 | 2024.11.03 |  트리  | [LCA](https://www.acmicpc.net/problem/11437) | [#19](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/19) |
 | 6차시 | 2024.11.05 |  자료구조  | [요세푸스 문제](https://www.acmicpc.net/problem/1158) | [#20](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/20) |
 | 7차시 | 2024.11.12 |  구현  | [치킨 배달](https://www.acmicpc.net/problem/15686) | [#25](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/25) |
+| 8차시 | 2024.11.17 |  구현  | [인구 이동](https://www.acmicpc.net/problem/16234) | [#28](https://github.com/AlgoLeadMe/AlgoLeadMe-12/pull/28) |
 ---

kokeunho/구현/8-kokeunho.java

@@ -0,0 +1,87 @@
+package org.example;
+
+import java.sql.SQLOutput;
+import java.util.*;
+
+public class Main {
+
+    static int N, R, L;
+    static int[][] map;
+    static boolean[][] visited;
+    static int[][] direction = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        N = sc.nextInt();
+        L = sc.nextInt();
+        R = sc.nextInt();
+
+        map = new int[N][N];
+
+        for(int i = 0; i < N; i++) {
+            for(int j = 0; j < N; j++) {
+                map[i][j] = sc.nextInt();
+            }
+        }
+
+        int day_count = 0;
+
+        while(true) {
+            visited = new boolean[N][N];
+            boolean moved = false;
+
+            for(int i = 0; i < N; i++) {
+                for(int j = 0; j < N; j++) {
+                    if(!visited[i][j]) {
+                        List<int[]> union = new ArrayList<> ();
+                        int populationSum = bfs(i, j, union);
+                        if(populationSum > 0) {
+                            moved = true;
+                            int newPopulation = populationSum / union.size();
+                            for(int[] country : union) {
+                                map[country[0]][country[1]] = newPopulation;
+                            }
+                        }
+                    }
+                }
+            }
+            if(!moved) {
+                break;
+            }
+            day_count++;
+        }
+
+        System.out.println(day_count);
+    }
+
+    private static int bfs(int x, int y, List<int[]> union) {
+        Queue<int[]> queue = new LinkedList<> ();
+        queue.add(new int[]{x, y});
+        union.add(new int[]{x, y});
+        visited[x][y] = true;
+        int populationSum = map[x][y];
+
+        while(!queue.isEmpty()) {
+            int[] now_position = queue.poll();
+            int nowX = now_position[0];
+            int nowY = now_position[1];
+
+            for(int[] dir : direction) {
+                int nx = nowX + dir[0];
+                int ny = nowY + dir[1];
+
+                if(nx >= 0 && nx < N && ny >= 0 && ny < N && !visited[nx][ny]) {
+                    int diff = Math.abs(map[nowX][nowY] - map[nx][ny]);
+                    if(diff >= L && diff <= R) {
+                        visited[nx][ny] = true;
+                        queue.add(new int[]{nx, ny});
+                        union.add(new int[]{nx, ny});
+                        populationSum += map[nx][ny];
+                    }
+                }
+            }
+        }
+        return union.size() > 1 ? populationSum : 0;
+    }
+}