One-Based Arithmetic
time limit per test
0.5 secondsmemory limit per test
256 megabytesinput
standard inputoutput
standard outputProf. Vasechkin wants to represent positive integer n as a sum of addends, where each addends is an integer number containing only 1s. For example, he can represent 121 as 121=111+11+–1. Help him to find the least number of digits 1 in such sum.
Input
The first line of the input contains integer n (1 ≤ n < 1015).
Output
Print expected minimal number of digits 1.
Sample test(s)
Input
121
Output
6
思路:一个数能够从比他大的数减,也能够从比它小的数的倍数加。
import java.util.*; public class Main { static long ones[]=new long[17]; static long dfs(long n,int i){ int k=(int) (n/ones[i]); n%=ones[i]; long count=k*i; if(n==0) return count; else return count+Math.min(i+dfs(ones[i]-n,i-1),dfs(n,i-1)); } public static void main(String[] args) { Scanner scan=new Scanner(System.in); long n=scan.nextLong(); ones[0]=0; for(int i=1;i<=16;i++){ ones[i]=ones[i-1]*10+1; } System.out.println(dfs(n,16)); } }