[20260228] BOJ / G5 / 계란으로 계란치기 / 김민진

zinnnn37/202602/28 BOJ G5 계란으로 계란치기.md

@@ -0,0 +1,81 @@
+```java
+import java.io.*;
+import java.util.StringTokenizer;
+
+public class BJ_16987_계란으로_계란치기 {
+
+    private static final BufferedReader  br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter  bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static       StringTokenizer st;
+
+    private static int N, ans;
+    private static int[][] eggs;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        sol();
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+
+        eggs = new int[N][2];
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+
+            eggs[i][0] = Integer.parseInt(st.nextToken());
+            eggs[i][1] = Integer.parseInt(st.nextToken());
+        }
+    }
+
+    private static void sol() throws IOException {
+        dfs(0, 0);
+
+        bw.write(ans + "");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void dfs(int depth, int broken) {
+        if (depth == N) {
+            ans = Math.max(ans, broken);
+            return;
+        }
+
+        if (eggs[depth][0] <= 0) {
+            dfs(depth + 1, broken);
+            return;
+        }
+
+        boolean canHit = false;
+
+        for (int i = 0; i < N; i++) {
+            if (i == depth) continue;
+            if (eggs[i][0] <= 0) continue;
+
+            canHit = true;
+
+            int beforeCur = eggs[depth][0];
+            int beforeOp  = eggs[i][0];
+
+            eggs[depth][0] -= eggs[i][1];
+            eggs[i][0] -= eggs[depth][1];
+
+            int brokenNow = 0;
+            if (beforeCur > 0 && eggs[depth][0] <= 0) brokenNow++;
+            if (beforeOp > 0 && eggs[i][0] <= 0) brokenNow++;
+
+            dfs(depth + 1, broken + brokenNow);
+
+            eggs[depth][0] = beforeCur;
+            eggs[i][0] = beforeOp;
+        }
+
+        if (!canHit) {
+            dfs(depth + 1, broken);
+        }
+    }
+
+}
+```