numbers Time Limit: 12000/6000 MS (Java/Others)    Memory Limit: 196608/196608 K (Java/Others)Total Submission(s): 156    Accepted Submission(s): 50 Problem Description   Now you have a stack and n numbers 1,2,3,…,n. These n numbers are pushed in the…

http://acm.hdu.edu.cn/showproblem.php?pid=5181 题意: 有一个栈,其中有n个数1~n按顺序依次进入栈顶,在某个时刻弹出. 其中m个限制,形如数字A必须在数字B之前弹出. 求方案总数   dp[i][j]表示数字i~j的出栈方案数 枚举最后一个出栈的数k,若k合法 dp[i][j]+=dp[i][k]*dp[k+1][j] 如何判断k是否合法?   对于一组i,j,k来说,它的弹出顺序是 [i,k-1]早于[k+1,j]早于k 对于一个限制 A必须在B…

题目:http://acm.hdu.edu.cn/showproblem.php?pid=5181 题解:https://www.cnblogs.com/Miracevin/p/10960717.html 原来卡特兰数的这个问题还能区间DP…… XO #include<cstdio> #include<cstring> #include<algorithm> #define ll long long using namespace std; int rdn() { ;;…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5522 水题:暴力过 #include<stdio.h> #include<string.h> #include<algorithm> #include<queue> #define MAX 10010 using namespace std; int main() { int n,m,j,i; int s[MAX]; int vis[MAX]; while(sc…

题目链接 参考. \(Description\) 将\(1,2,\cdots,n(n\leq 300)\)依次入栈/出栈,并满足\(m(m\leq 90000)\)个形如\(x\)要在\(y\)之前出栈的限制,问合法的出栈序列有多少种. \(Solution\) 没有限制就是个卡特兰数,但有了限制就要考虑好好DP了.. 序列的入栈&出栈顺序可以构成一棵二叉树,且每一棵子树中的点一定比该子树的根节点出栈早. \(f[i][j]\)表示子树根节点为\(i\),其中的点是\(i\sim j\),\(i…

题目传送门 /* 找规律/数位DP:我做的时候差一点做出来了,只是不知道最后的 is_one () http://www.cnblogs.com/crazyapple/p/3315436.html 数位DP:http://blog.csdn.net/libin56842/article/details/11580497 */ #include <cstdio> #include <iostream> #include <algorithm> #include <c…

HDOJ(HDU).1058 Humble Numbers (DP) 点我挑战题目 题意分析 水 代码总览 /* Title:HDOJ.1058 Author:pengwill Date:2017-2-15 */ #include <iostream> #include <cstdio> #include <algorithm> #include <cstring> #define nmax 6000 #define min(a,b) (a<b?a:b…

A sequence of numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4384    Accepted Submission(s): 1374 Problem Description Xinlv wrote some sequences on the paper a long time ago, they might…

Problem Description Give you a lot of positive integers, just to find out how many prime numbers there are. Input There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won't exceed 32-…

Problem Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 24, 25, 27, - shows the first 20 humble numbers. Write a program to find and print…