240513 타노스

public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	StringBuilder sb = new StringBuilder();

	char[] s = br.readLine().toCharArray();
	int[] cnt = new int[2];

	for (char c : s) {
		int num = c - '0';
		cnt[num]++;
	}

	cnt[1] = (s.length - cnt[0]) / 2;
	cnt[0] /= 2;

	int deletedOnes = 0;
	int deletedZeros = 0;

	for (char c : s) {
		if (c == '1') {
			if (deletedOnes < cnt[1]) {
				deletedOnes++;
			} else {
				sb.append(1);
			}
		} else {
			if (deletedZeros < cnt[0]) {
				sb.append(0);
				deletedZeros++;
			}
		}
	}
	sb.append("\n");

	System.out.print(sb.toString());
}

출처:https://www.acmicpc.net/problem/20310