贪心法 import java.util.Scanner; public class Two { private static long n; private static String result; public static void main(String[] args){ read(); solve(); printResult(); } private static void read() { //System.setIn(Main.class.getResourceAsStream("file.txt")); Scanner scanner = new Scanner(System.in); n = scanner.nextLong(); scanner.close(); } private static void solve() { result = "" + (n < 0 ? getStep(n * (-1)) :getStep(n)); } private static void printResult() { System.out.println(result); } private static long getStep(long n) { if(n < 4) return n; if(n % 2 == 0){ return getStep(n/2) + 1; } else { return Math.min(getStep((n - 1)/2) + 2, getStep((n + 1)/2)+ 2) ; } } }