240710 1의 개수 세기

static long a;
static long b;
static long[] dp = new long[57];

public static void main(String[] args) throws Exception {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	StringTokenizer st = new StringTokenizer(br.readLine());
	a = Long.parseLong(st.nextToken());
	b = Long.parseLong(st.nextToken());

	dp[0] = 1;
	for (int i = 1; i < 56; i++) {
		dp[i] = 2 * dp[i - 1] + (1L << i);
	}

	System.out.println(countOnes(b) - countOnes(a - 1));
}

static long countOnes(long n) {
	if (n < 0) return 0;

	long count = n & 1;
	int bits = (int) (Math.log(n) / Math.log(2));

	for (int i = bits; i > 0; i--) {
		if ((n & (1L << i)) == 0) continue;

		count += dp[i - 1] + (n - (1L << i) + 1);
		n -= (1L << i);
	}

	return count;
}

출처:https://www.acmicpc.net/problem/9527