题解 | #游游的字母翻倍#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        int length = in.nextInt();
        int n = in.nextInt();

        String s = in.next();
        StringBuilder buff = new StringBuilder(s);

        int a,b;
        for(int t = 0; t<n; t++){
            a = in.nextInt();
            b = in.nextInt();
            for(int i = a-1 ; i<b  ; i+=2){
                buff.insert(i,buff.charAt(i));
                b++;
            }
        }

        System.out.println(buff);
    }
}