这是一道典型的DFS题目.幻想有n个箱子,每次都向箱子里扔一个数,(当然第一个是必定是1,因为题目要求按字典序输出).判断输出的条件就是,当我移动到第n+1个箱子的时候,就要return了,当然还要判断是否能输出..怎么判断能否输出呢?题目说:组成一个圈子,a[j]+a[j+1]都必须是质数.但是,如果我们在n+1的时候再判断这个,已经很迟了,递归次数太多了.所以,应该是当满足这个条件,我才递归. 当然,a[1]+a[n]是需要在输出的时候判定的 #include <stdio.h> #inc…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3714 懂了三分思想和F(x)函数的单调性质,这题也就是水题了 #include "stdio.h" //最后得到的F(x)函数要么是单调的,要么是先减后增的,有了这个性质,就可以三分了~ #include "string.h" #define N 10005 #define eps 1e-9 #define INF 0x3fffffff struct node { in…

http://acm.hdu.edu.cn/showproblem.php?pid=3714 [题意]: 题目意思看了很久很久,简单地说就是给你n个二次函数,定义域为[0,1000], 求x在定义域中每个x所在的n个函数的最大值的最小值.很拗口吧,显然这题不是组队或者耐心的做是不知道性质的,至少我没看出来.网上说是三分,我画了几个图,确实是.根据二次函数的性质,增长的快慢已经确定了,那的确是单峰的.那就OK了.另外eps的问题1e-8还是wa,1e-9AC.想了下,因为有系数a,b,c的缘故,一…

Error Curves Time Limit:3000MS    Memory Limit:0KB    64bit IO Format:%lld & %llu SubmitStatusPracticeUVALive 5009 Appoint description: Description Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a met…

Error Curves Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 1198    Accepted Submission(s): 460 Problem Description Josephina is a clever girl and addicted to Machine Learning recently. She pa…

Error Curves 思路:这个题的思路和上一个题的思路一样,但是这个题目卡精度,要在计算时,卡到1e-9. #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #define MAXN 10100 #define eps 1e-9 using namespace std; int T,n; double ans; double l,r,mid1,mid2;…

Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a method called Linear Discriminant Analysis, which has many interesting properties. In order to test the algorithm's efficiency, she collects many datas…

Error Curves Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 4137    Accepted Submission(s): 1549 Problem Description Josephina is a clever girl and addicted to Machine Learning recently. Shepay…

1.HDU 2087 2.题意:一个主串,一个子串,求子串在主串里出现了几次. 3.总结:看了题解,还是不太懂.. //#include<iostream>#include<cmath>#include<queue>#include<algorithm> //不明白为什么加上这些头文件就Compilation Error #include<cstring> #include<cstdio> using namespace std; #…

HDU 模拟题, 枚举1002 1004 1013 1015 1017 1020 1022 1029 1031 1033 1034 1035 1036 1037 1039 1042 1047 1048 1049 1050 1057 1062 1063 1064 1070 1073 1075 1082 1083 1084 1088 1106 1107 1113 1117 1119 1128 1129 1144 1148 1157 1161 1170 1172 1177 1197 1200 1201…