complete [W6] 계란으로 계란치기

week6/KBC/boj_16987.java

@@ -0,0 +1,57 @@
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+public class Main {
+    static int max;
+    static int n;
+    static boolean[] isBroken;
+    static int[][] eggs;
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        n = Integer.parseInt(br.readLine());
+        max = 0;
+        eggs = new int[n][2];
+        isBroken = new boolean[n];
+        for(int i=0; i<n; i++) {
+            int[] input = Arrays.stream(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
+            eggs[i][0] = input[0];
+            eggs[i][1] = input[1];
+        }
+        dfs(0,0);
+        System.out.println(max);
+    }
+    public static void dfs(int index, int count) {
+        max = Math.max(count, max);
+        if(index >= n) {
+            return;
+        }
+        if(eggs[index][0] <= 0) {
+            dfs(index+1, count);
+            return;
+        }
+
+        for(int i=0; i<n; i++) {
+            if(i == index) continue;
+            if(eggs[index][0] <= 0 || eggs[i][0] <= 0) continue; //이미 깨졌으면
+            attack(index, i);
+            dfs(index+1, count + countBrokenEgg(index ,i));
+            restore(index, i);
+        }
+    }
+    private static int countBrokenEgg(int e1, int e2) {
+        int count = 0;
+        if(eggs[e1][0] <= 0) count++;
+        if(eggs[e2][0] <= 0) count++;
+        return count;
+    }
+    private static void attack(int e1, int e2) {
+        eggs[e1][0] -= eggs[e2][1];
+        eggs[e2][0] -= eggs[e1][1];
+    }
+    private static void restore(int e1, int e2) {
+        eggs[e1][0] += eggs[e2][1];
+        eggs[e2][0] += eggs[e1][1];
+    }
+}