[20250909] BOJ / G4 / 전구와 스위치 / 이인희

LiiNi-coder/202509/09 BOJ 전구와 스위치.md

@@ -0,0 +1,46 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        var br = new BufferedReader(new InputStreamReader(System.in));
+        int n = Integer.parseInt(br.readLine());
+        char[] src = br.readLine().toCharArray();
+        char[] dst = br.readLine().toCharArray();
+        int answer = process(Arrays.copyOf(src, n), dst, false);
+        answer = Math.min(answer, process(Arrays.copyOf(src, n), dst, true));
+
+        System.out.println(answer == Integer.MAX_VALUE ? -1 : answer);
+    }
+    static int process(char[] s, char[] target, boolean firstPress) {
+        int count = 0;
+        // 첫번째 토글로 그리디 분기
+        if (firstPress) {
+            toggle(s, 0);
+            toggle(s, 1);
+            count++;
+        }
+        for (int i = 1; i < s.length; i++) {
+            if (s[i - 1] != target[i - 1]) {
+                toggle(s, i - 1);
+                toggle(s, i);
+                if (i + 1 < s.length)
+                    toggle(s, i + 1);
+                count++;
+            }
+        }
+
+        for (int i = 0; i < s.length; i++) {
+            if (s[i] != target[i]) return Integer.MAX_VALUE;
+        }
+        return count;
+    }
+
+    static void toggle(char[] arr, int i) {
+        arr[i] = arr[i] == '0' ? '1' : '0';
+    }
+}
+```