Merge pull request #1035 from AlgorithmWithGod/lkhyun

[20251004] BOJ / G4 / 전구와 스위치 / 이강현

Author: ShinHeeEul

lkhyun/202510/04 BOJ G4 전구와 스위치.md

@@ -0,0 +1,75 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main{
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static StringBuilder sb = new StringBuilder();
+    static int N;
+    static int[] input;
+    static int[] target;
+    static int cnt1 = 0;
+    static int cnt2 = 0;
+
+    public static void main(String[] args) throws Exception {
+        N = Integer.parseInt(br.readLine());
+        input = new int[N];
+        target = new int[N];
+
+        String temp1 = br.readLine();
+        String temp2 = br.readLine();
+        
+        for(int i = 0;i<N;i++){
+            input[i] = Character.getNumericValue(temp1.charAt(i));
+            target[i] = Character.getNumericValue(temp2.charAt(i));
+        }
+        int[] input1 = input.clone();
+        int[] input2 = input.clone();
+
+        for(int i = 1; i<N; i++){
+            if(input1[i-1] != target[i-1]){
+                input1[i-1] ^= 1;
+                input1[i] ^= 1;
+                if(i+1 < N) {
+                    input1[i + 1] ^= 1;
+                }
+                cnt1++;
+            }
+        }
+        for (int i = 0; i < N; i++) {
+            if(input1[i] != target[i]){
+                cnt1 = Integer.MAX_VALUE;
+                break;
+            }
+        }
+
+        input2[0] ^= 1;
+        input2[1] ^= 1;
+        cnt2++;
+        for (int i = 1; i < N; i++) {
+            if(input2[i-1] != target[i-1]){
+                input2[i-1] ^= 1;
+                input2[i] ^= 1;
+                if(i+1 < N) {
+                    input2[i + 1] ^= 1;
+                }
+                cnt2++;
+            }
+        }
+        for (int i = 0; i < N; i++) {
+            if(input2[i] != target[i]){
+                cnt2 = Integer.MAX_VALUE;
+                break;
+            }
+        }
+        int cnt = Math.min(cnt1, cnt2);
+        if(cnt == Integer.MAX_VALUE){
+            cnt = -1;
+        }
+        bw.write(cnt+"");
+        bw.close();
+    }
+}
+```