15659 - 연산자 끼워넣기 (3) (백트래킹 + 덱 + 브루트포스)

Author: zeesouth

README.md

@@ -326,12 +326,13 @@
 </details>
 
 <details>
-<summary><a href="https://www.acmicpc.net/problemset?sort=ac_desc&algo=125"> 부루트포스 (Brute Force)</a></summary>
+<summary><a href="https://www.acmicpc.net/problemset?sort=ac_desc&algo=125"> 브루트포스 (Brute Force)</a></summary>
 <div markdown="1">       
 <pre>
 - <a href="https://www.acmicpc.net/problem/15660">15660. 테르토미노 (2)</a>
 - <a href="https://www.acmicpc.net/problem/1025">1025. 제곱수 찾기</a>
 - <a href="https://www.acmicpc.net/problem/1954">1954. 화학실험</a>
+- <a href="https://www.acmicpc.net/problem/15659">15659. 연산자 끼워넣기 (3)</a>
 </pre>
 </div>
 </details>

src/bruteForce/n15659/Main.java

@@ -0,0 +1,76 @@
+package bruteForce.n15659;
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static StringTokenizer st;
+    static int N, max = Integer.MIN_VALUE, min = Integer.MAX_VALUE;
+    static int[] num, select, operator = new int[4]; // +, -, *, /
+
+    public static void main(String[] args) throws Exception {
+        init();
+        dfs(0);
+        System.out.println(max);
+        System.out.println(min);
+    }
+
+    private static void dfs(int idx) {
+        if (idx == N - 1) {
+            calculate();
+            return;
+        }
+
+        for (int i = 0; i < 4; i++) {
+            if (operator[i] == 0) continue;
+
+            select[idx] = i;
+            operator[i]--;
+            dfs(idx + 1);
+            operator[i]++;
+        }
+    }
+
+    private static void calculate() {
+        Deque<Integer> oq = new LinkedList<>();
+        Deque<Integer> nq = new LinkedList<>();
+        nq.offer(num[0]);
+
+        for (int i = 0; i < N - 1; i++) {
+            if (select[i] <= 1) {
+                oq.offerLast(select[i]);
+                nq.offerLast(num[i + 1]);
+            } else if (select[i] == 2) {
+                nq.offerLast(nq.pollLast() * num[i + 1]);
+            } else {
+                nq.offerLast(nq.pollLast() / num[i + 1]);
+            }
+        }
+
+        int res = nq.poll();
+
+        while (!oq.isEmpty()) {
+            int o = oq.poll();
+            int n = nq.poll();
+
+            if (o == 0) res += n;
+            else res -= n;
+        }
+
+        max = Math.max(res, max);
+        min = Math.min(res, min);
+    }
+
+    private static void init() throws Exception {
+        N = Integer.parseInt(br.readLine());
+        num = new int[N];
+        select = new int[N - 1];
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) num[i] = Integer.parseInt(st.nextToken());
+
+        st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < 4; i++) operator[i] = Integer.parseInt(st.nextToken());
+    }
+}