雪霜贸贸，荠麦之茂

给定一个字符串hash，为 ∑i=0len−1str[i]×31len−1−i 求 K个长度不超过 1000的字符串，使得他们的 hash值相等 其中每个 hash值是 32位有符号整数，K≤1000 思路：将字符串看成是31进制，前一位-1，后一位+31，转换成十进制的结果是不变的#include<stdio.h>#include<string.h>using namespace s

The frequent subset problem is defined as follows. Suppose UU={1, 2,\ldots…,N} is the universe, and S_{1}S ​1 ​​ , S_{2}S ​2 ​​ ,\ldots…,S_{M}S ​M ​​ are MM sets over UU. Given a positive constan