求给定序列中长度为M的上升子序列个数.$N,M<=1000$. 很容易想到方法.$f[i,j]$表示以第$i$个数结尾,长度为$j$的满足要求子序列个数.于是转移也就写出来了$f[i][j]+=f[k][j-1]$   $(k<i且A_k<A_i)$.边界$f[0][0]=1$. 然后这是$O(N^2 M)$的.考虑优化.每次由于只从$j-1$也就是上一层状态中选在自己序号之前且比自己小的数来转移,用时间保证第一个要求,第二个要求,将每个数离散化一下,用$m$层的BIT维护以离散化值为下…

C - The Battle of Chibi Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 无 Description Cao Cao made up a big army and was going to invade the whole South China. Yu Zhou was worried about it. He thought the only way to beat Cao Cao is to have a spy in Cao…

The Battle of Chibi Time Limit: 6000/4000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 2899    Accepted Submission(s): 1043 Problem Description Cao Cao made up a big army and was going to invade the whole South Ch…

C - The Battle of Chibi Description Cao Cao made up a big army and was going to invade the whole South China. Yu Zhou was worried about it. He thought the only way to beat Cao Cao is to have a spy in Cao Cao's army. But all generals and soldiers of C…

题意: 给你一个长度为n的数组,你需要从中找一个长度为m的严格上升子序列 问你最多能找到多少个 题解: 我们先对原序列从小到大排序,排序之后的序列就是一个上升序列 这里如果两个数相等的话,那么因为题目要我们求严格上升子序列,所以我们让这个数在数组中原来位置靠后的排序之后让它靠前(靠前也就是下标小)   我们dp方程:dp[i][j]表示截至到第i(这个i是按照没排序之前的下标)个元素,上升子序列长度为j的子序列能找到dp[i][j]个 dp转移方程:dp[i][j]=dp[1--i-1][j-1…

题意:给你一个n个数的序列,要求从中找出含m个数的严格递增子序列,求能找出多少种不同的方案 dp[i][j]表示以第i个数结尾,形成的严格递增子序列长度为j的方案数 那么最终的答案应该就是sigma(dp[i][m]); 显然有:dp[i][j] = sigma(dp[k][j - 1]); 其中 1 <= k < i 且 a[k] < a[i]; 题目要求严格递增,这个限制怎么解决? hdu4719这道题同样是这样处理,即我们只需要从小到大dp就行了. 但是复杂度是O(n^3)的,显然…

题目链接:http://acm.uestc.edu.cn/#/problem/show/1217 给你一个长为n的数组,问你有多少个长度严格为m的上升子序列. dp[i][j]表示以a[i]结尾长为j的上升子序列个数.常规是三个for. 这里用树状数组优化一下,类似前缀和的处理,两个for就好了. //#pragma comment(linker, "/STACK:102400000, 102400000") #include <algorithm> #include &l…

题意 给出长度为n的序列,问这个序列中有多少个长度为m的单调递增子序列. \(1\le M\le N\le 1000\) 分析 用F[i,j]表示前j个数构成以Aj为结尾的数列中,长度为i的严格递增子序列有多少个 \[ F[i,j]=\sum_{k<j\wedge A_k<A_j}F[i-1,k] \] 复杂度\(O(mn^2)\). 观察到决策集合的变化一是只增不减,二是有一个前缀范围,用树状数组维护转移即可.时间复杂度\(O(mn\log n)\) 代码 #include<iostr…

The Battle of Chibi Cao Cao made up a big army and was going to invade the whole South China. Yu Zhou was worried about it. He thought the only way to beat Cao Cao is to have a spy in Cao Cao's army. But all generals and soldiers of Cao Cao were loya…

The Battle of Chibi Time Limit: 6000/4000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 591    Accepted Submission(s): 192 Problem Description Cao Cao made up a big army and was going to invade the whole South Chin…