题目链接: C. Subsequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output For the given sequence with n different elements find the number of increasing subsequences with k + 1 elements. It is…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2227 Find the nondecreasing subsequences                                  Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)                                             …

E. Hanoi Factory time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Of course you have heard the famous task about Hanoi Towers, but did you know that there is a special factory producing the…

//树形DP+树状数组 HDU 5877 Weak Pair // 思路:用树状数组每次加k/a[i],每个节点ans+=Sum(a[i]) 表示每次加大于等于a[i]的值 // 这道题要离散化 #include <bits/stdc++.h> using namespace std; #define LL long long typedef pair<int,int> pii; const double inf = 123456789012345.0; const LL MOD…

1264: [AHOI2006]基因匹配Match Time Limit: 10 Sec  Memory Limit: 162 MBSubmit: 793  Solved: 503[Submit][Status][Discuss] Description 基 因匹配(match) 卡卡昨天晚上做梦梦见他和可可来到了另外一个星球,这个星球上生物的DNA序列由无数种碱基排列而成(地球上只有4种),而更奇怪的是,组成DNA序列的 每一种碱基在该序列中正好出现5次!这样如果一个DNA序列有N种不同的碱基…

题目描述 Farmer John's N (1 <= N <= 100,000) cows are lined up in a row andnumbered 1..N. The cows are conducting another one of their strangeprotests, so each cow i is holding up a sign with an integer A_i(-10,000 <= A_i <= 10,000). FJ knows the…

奶牛抗议 DP 树状数组 USACO的题太猛了 容易想到\(DP\),设\(f[i]\)表示为在第\(i\)位时方案数,转移方程: \[ f[i]=\sum f[j]\;(j< i,sum[i]-sum[j]\ge0) \] \(O(n^2)\)过不了,考虑优化 移项得: \[ f[i]=\sum f[j]\;(j< i,sum[i]\ge sum[j]) \] 这时候我们发现相当于求在\(i\)前面并且前缀和小于\(sum[i]\)的所有和,这就可以用一个树状数组优化了,在树状数组维护下标为…

题目链接 http://codeforces.com/problemset/problem/597/C 题意 给出一个n 一个 k 求 n 个数中 长度为k的上升子序列 有多少个 思路 刚开始就是想用dp 复杂度 大概是 O(n ^ 2 * k) T了 但是 思路还是一样的 只是用树状数组 优化了一下 第三层循环 dp[i][j] 表示 第 i 个数 长度为 j 时 那么 dp[i][j] 的状态转移就是 ∑(arr[i] > arr[k] ? : dp[k][j - 1] ) AC代码 #in…

Sereja has a sequence that consists of n positive integers, a1, a2, ..., an. First Sereja took a piece of squared paper and wrote all distinct non-empty non-decreasing subsequences of sequence a. Then for each sequence written on the squared paper, S…

题目链接:http://codeforces.com/contest/909/problem/C 题意: Python是没有大括号来标明语句块的,而是用严格的缩进来体现. 现在有一种简化版的Python,只有两种语句: (1)'s'语句:Simple statements. 相当于一般语句. (2)'f'语句:For statements. 相当于for循环,并且规定它的循环体不能为空. 然后给你一段没有缩进的Python程序,共n行(n <= 5000). 问你添加缩进后,有多少种合法且不同的…