HDU 4945 2048 题目链接 题意:给定一个序列,求有多少个子序列能合成2048 思路:把2,4,8..2048这些数字拿出来考虑就能够了,其它数字不管怎样都不能參与组成.那么在这些数字基础上,dp[i][j]表示到第i个数字,和为j的情况数,然后对于每一个数枚举取多少个,就能够利用组合数取进行状态转移,这里有一个剪枝,就是假设加超过2048了,那么后面数字的组合数的和所有都是加到2048上面,能够利用公式一步求解,这种整体复杂度就能够满足题目了.然后这题时限卡得紧啊.10W内的逆元不先…

思路: 这个题写了一个背包的解法,超时了.搜了下题解才发现我根本不会做. 思路参见这个: 其实我们可以这样来考虑,求补集,用全集减掉不能组成2048的集合就是答案了. 因为只要达到2048就可以了,所以求补集会大大减小枚举的次数. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> #include <…

题意:给n(n<=100,000)个数,0<=a[i]<=2048 .一个好的集合要满足,集合内的数可以根据2048的合并规则合并成2048 .输出好的集合的个数%998244353 . 比赛的时候想着1跟3可以合并成4 ....然后就越搞越复杂了.....2048玩得不多的我没有透彻的合并规则概念..... 看了题解写了发,妥妥地TLE...本地随意n=100,000都TLE了... 用dp[i][j]表示当前 i个2^j 的方案数 然后队友提醒优化,就是,当枚举到比如,value =…

2048 Time Limit: 3000/1500 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 840    Accepted Submission(s): 199 Problem Description Teacher Mai is addicted to game 2048. But finally he finds it's too hard to get 2048.…

2048 Problem Description Teacher Mai is addicted to game 2048. But finally he finds it's too hard to get 2048. So he wants to change the rule: You are given some numbers. Every time you can choose two numbers of the same value from them and merge the…

http://acm.hdu.edu.cn/showproblem.php? pid=4123 Problem Description Bob wants to hold a race to encourage people to do sports. He has got trouble in choosing the route. There are N houses and N - 1 roads in his village. Each road connects two houses,…

http://acm.hdu.edu.cn/showproblem.php?pid=4507 Problem Description 单身! 依旧单身! 吉哥依旧单身! DS级码农吉哥依旧单身! 所以.他生平最恨情人节,无论是214还是77.他都讨厌! 吉哥观察了214和77这两个数,发现: 2+1+4=7 7+7=7*2 77=7*11 终于,他发现原来这一切归根究竟都是由于和7有关!所以,他如今甚至讨厌一切和7有关的数. 什么样的数和7有关呢? 假设一个整数符合以下3个条件之中的一个.那么我…

http://acm.hdu.edu.cn/showproblem.php?pid=3709 Problem Description A balanced number is a non-negative integer that can be balanced if a pivot is placed at some digit. More specifically, imagine each digit as a box with weight indicated by the digit.…

XHXJ's LIS Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2265    Accepted Submission(s): 927 Problem Description #define xhxj (Xin Hang senior sister(学姐)) If you do not know xhxj, then careful…

You Are the One Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 3348    Accepted Submission(s): 1524 Problem Description The TV shows such as You Are the One has been very popular. In order to m…