240612 전구와 스위치

static int n;
static int ans = Integer.MAX_VALUE;
static char[] lights;
static char[] objLights;
static char[] tempLights;

public static void main(String[] args) throws Exception {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	
	n = Integer.parseInt(br.readLine());
	lights = br.readLine().toCharArray();
	objLights = br.readLine().toCharArray();
	
	tempLights = lights.clone();
	solve(0, false);
	
	tempLights = lights.clone();
	switchLight(0);
	switchLight(1);
	solve(1, true);
	
	System.out.println(ans == Integer.MAX_VALUE ? -1 : ans);
	br.close();
}

public static void solve(int count, boolean firstSwitched) {
	for (int i = 1; i < n; i++) {
		if (tempLights[i - 1] != objLights[i - 1]) {
			count++;
			push(i);
		}
	}
	
	if (tempLights[n - 1] == objLights[n - 1]) {
		ans = Math.min(ans, count);
	} else if (firstSwitched && count == 1) {
		ans = -1;
	}
}

public static void push(int i) {
	switchLight(i - 1);
	switchLight(i);
	if (i != n - 1) {
		switchLight(i + 1);
	}
}

public static void switchLight(int i) {
	tempLights[i] = (tempLights[i] == '0') ? '1' : '0';
}

출처:https://www.acmicpc.net/problem/2138