题解 | #鸡鸭分类问题#

//招商银行真题，鸡鸭同笼问题

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String jiya = sc.nextLine();
        char[] cd = jiya.toCharArray();
        int num_c = 0 , num_d = 0 ,sum1 = 0 , sum2 = 0;
        for (char cd1 : cd) {
            if(cd1 == 'C'){num_c ++;}
            if(cd1 == 'D'){sum1 += num_c;}

        }
        for (char cd1 : cd) {
            if(cd1 == 'D'){num_d ++;}
            if(cd1 == 'C'){sum2 += num_d;}

        }
        int sum = Math.min(sum1,sum2);
        System.out.println(sum);

    }
}