김형민: 치킨 배달

HyeongMinKim/week09/치킨배달.java

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+import java.io.*;
+import java.util.ArrayList;
+import java.util.StringTokenizer;
+
+class Main {
+    static int n, m;
+    static ArrayList<Node> home = new ArrayList<>();
+    static ArrayList<Node> chicken = new ArrayList<>();
+    static boolean open[];
+    static int result = Integer.MAX_VALUE;
+
+    static class Node {
+        int x, y;
+
+        public Node(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        n = Integer.parseInt(st.nextToken());
+        m = Integer.parseInt(st.nextToken());
+
+        for (int i = 0; i < n; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < n; j++) {
+                String now = st.nextToken();
+                if (now.equals("1")) home.add(new Node(i, j));
+                else if (now.equals("2")) chicken.add(new Node(i, j));
+            }
+        }
+
+        open = new boolean[chicken.size()];
+
+        backtrack(0, 0);
+        bw.write(result + "\n");
+        bw.flush();
+    }
+
+    static void backtrack(int start, int select) {
+        if (select == m) {
+            int sum = 0; // 치킨 거리
+            for (int i = 0; i < home.size(); i++) {
+                int res = Integer.MAX_VALUE; // i번째 집에서 치킨 집까지 걸리는 최소 거리
+                for (int j = 0; j < chicken.size(); j++) {
+                    if (!open[j]) continue;
+                    int distance = Math.abs(chicken.get(j).x - home.get(i).x) + Math.abs(chicken.get(j).y - home.get(i).y);
+                    res = Math.min(res, distance);
+                }
+                sum += res;
+            }
+            result = Math.min(result, sum);
+            return;
+        }
+
+        for (int i = start; i < chicken.size(); i++) {
+            open[i] = true;
+            backtrack(i + 1, select + 1);
+            open[i] = false;
+        }
+    }
+
+}