HackerRank

Solution 1: https://www.hackerrank.com/challenges/number-list/editorial

Reversed thought: total no. of subsets  -  no. of subsets without arr[i] > k

Solution 2: constructive solution:

http://www.martinkysel.com/hackerrank-number-list-solution/

原文地址:https://www.cnblogs.com/tonix/p/4493552.html