[20250921] BOJ / G4 / 빠른 무작위 메시지 전달 / 한종욱

Ukj0ng/202509/21 BOJ G4 빠른 무작위 메시지 전달.md

@@ -0,0 +1,85 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static int[][] groups = {
+            {0, 0}, {1, 2}, {3, 4}, {5, 6}, {7, 8}, {9, 10}, {11, 12}
+    };
+    private static int[] combination, firstInGroup;
+    private static boolean[] visited;
+    private static int[][] times;
+    private static int minTime = Integer.MAX_VALUE;
+
+    public static void main(String[] args) throws IOException {
+        init();
+
+        DFS(1);
+        bw.write(minTime + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        times = new int[13][13];
+        combination = new int[7];
+        firstInGroup = new int[7];
+        visited = new boolean[7];
+
+        for (int i = 1; i <= 12; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for (int j = 1; j <= 12; j++) {
+                times[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+    }
+
+    private static void DFS(int index) {
+        if (index == 7) {
+            for (int mask = 0; mask < (1 << 6); mask++) {
+                for (int i = 1; i <= 6; i++) {
+                    firstInGroup[i] = ((mask >> (i - 1)) & 1) == 0 ? 0 : 1;
+                }
+                int totalTime = cal();
+                minTime = Math.min(minTime, totalTime);
+            }
+            return;
+        }
+
+        for (int i = 1; i <= 6; i++) {
+            if (!visited[i]) {
+                visited[i] = true;
+                combination[index] = i;
+                DFS(index + 1);
+                visited[i] = false;
+            }
+        }
+    }
+
+    private static int cal() {
+        int totalTime = 0;
+        int prevStudent = -1;
+
+        for (int i = 1; i <= 6; i++) {
+            int index = combination[i];
+            int[] group = groups[index];
+            int first = group[firstInGroup[index]];
+            int second = group[1 - firstInGroup[index]];
+
+            if (i == 1) {
+                totalTime += times[first][second];
+                prevStudent = second;
+            } else {
+                totalTime += times[prevStudent][first];
+                totalTime += times[first][second];
+                prevStudent = second;
+            }
+        }
+
+        return totalTime;
+    }
+}
+```