[编程题] 调整队形代码

import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while(in.hasNext()) {
            String s = in.next();
            System.out.println(solve(s));
        }
         
    }
     
    private static int solve(String s) {
         
        int toleft = 0;
        int toright = s.length()-1;
         
        int leftcost = 0;
        int rightcost = 0;
         
        for(int i=0;i<s.length();i++) {
            if(s.charAt(i) == 'B') {
                leftcost += i-toleft;
                toleft++;
                rightcost += toright - i;
                toright--;
            }
        }
         
        return Math.min(leftcost, rightcost);
    }
}