关于哈夫曼编码与哈夫曼树的介绍,可以看这个视频

题目链接

以3,4,5,6为例构造哈夫曼树

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        PriorityQueue<Long> heap = new PriorityQueue<>();
        while(n-- != 0) {
            long x = in.nextLong();
            heap.offer(x);
        }
        
        //构建哈夫曼树
        long ret = 0;
        while(heap.size() > 1) {
            long t1 = heap.poll();
            long t2 = heap.poll();
            heap.offer(t1 + t2);
            ret += t1 + t2;
        }

        System.out.print(ret);
    }
}