This problem is in Contest(s) below:
Contest 1403:【算法设计与分析】实验七
Contest 1404:【算法设计与分析】实验7 贪心算法
Contest 1530:算法实验7
Contest 1742:【算法设计与分析】实验7 (计算机24-1/2)
Contest 1743:【算法设计与分析】实验7 (区块链24-1、2+计算机24-5/6/9/10)