[20250716] BOJ / G4 / 문자열 폭발 / 이종환

0224LJH/202507/16 BOJ 문자열 폭발.md

@@ -0,0 +1,131 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+
+    static HashMap<Character,Integer> boomWord = new HashMap<>();
+    static StringBuilder sb = new StringBuilder();
+    static Char[] chars;
+
+    static class Char{
+
+        Char pre = null;
+        Char post = null;
+        char ch;
+        boolean isAlive = true;
+
+        public Char(char ch){
+            this.ch = ch;
+        }
+
+        public boolean checkBoom(int idx){
+
+            if (boomWord.containsKey(ch) && boomWord.get(ch) == idx) {
+                if (idx == boomWord.size()-1) return true;
+                if (post== null) return false;
+
+                return post.checkBoom(idx+1);
+            }
+            return false;
+        }
+
+        public Char boom(){
+            return processBoom(pre,0);
+        }
+        private Char processBoom(Char pre, int idx){
+            if (idx == boomWord.size()){
+
+                if (this.pre != null && pre != null) {
+                    this.pre = pre;
+                    pre.post = this;
+                }
+
+                return this;
+            }
+            isAlive = false;
+
+            if ( idx == boomWord.size()-1 && this.post == null) {
+                if (pre != null )pre.post = null;
+                return pre;
+            }
+            return post.processBoom(pre,idx+1);
+        }
+
+        public Char doReposition(){
+            // 폭발단어에 포함안되면 굳이 이동 필요 x;
+            if (!boomWord.containsKey(ch)) return this;
+
+            int curIdx = boomWord.get(ch);
+            return moveToFirst(curIdx);
+        }
+
+        private Char moveToFirst(int idx){
+            if (idx == 0 || pre == null ) return this;
+            if (!boomWord.containsKey(ch) || boomWord.get(ch) != idx) return this;
+
+            return pre.moveToFirst(idx-1);
+
+        }
+    }
+
+
+
+    public static void main(String[] args) throws IOException {
+        init();
+        process();
+        print();
+    }
+
+    private static void init() throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        String input =  br.readLine();
+
+        chars = new Char[input.length()];
+        chars[0] = new Char(input.charAt(0));
+        for (int i = 1; i < chars.length; i++) {
+            chars[i] = new Char(input.charAt(i));
+            chars[i].pre = chars[i-1];
+            chars[i-1].post = chars[i];
+        }
+
+        String target = br.readLine();
+
+        for (int i = 0; i < target.length(); i++) {
+            boomWord.put(target.charAt(i), i);
+        }
+
+    }
+
+    private static void process() {
+
+        Char cur = chars[0];
+
+        while (cur != null) {
+            if(cur.checkBoom(0)){
+                cur = cur.boom();
+                if (cur != null) cur = cur.doReposition();
+            } else{
+                cur = cur.post;
+            }
+        }
+
+
+        for (int i = 0; i < chars.length; i++) {
+            if (chars[i].isAlive) sb.append(chars[i].ch);
+        }
+
+
+
+    }
+
+
+
+
+    private static void print() {
+        System.out.println(sb.length()==0 ? "FRULA" : sb.toString());
+    }
+}
+```