Keen On Everything But Triangle 感觉最近多校好多主席树的亚子,但是本人菜得很,还没学过主席树,看着队友写题就只能划水,\(WA\)了还不能帮忙\(debug\),所以深思熟虑之后决定学习一下主席树. 题意 问在\([l,r]\)区间内取三个数字构成三角形,问能构成的三角形最大的周长是多少?如果不能构成三角形输出\("-1"\). 思路 三角形构成的条件: 三条边 两边之和大于第三边 然后呢,我们要找最大的周长,那么我们很容易想到取最大的三条边,如果不行就…

题意: 有\(n\)根长度不一的棍子,q次询问,求\([L,R]\)区间的棍子所能组成的周长最长的三角形.棍长\(\in [1, 1e9]\),n\(\in [1, 1e5]\). 思路: 由于不构成三角形的数组为菲波那切数列,所以当棍数超过44时,长度超过1e9,所以从最大开始数最多不超过45次就能找到构成三角形.所以直接主席树查询区间第k大.复杂度\(O(45 * q * logn)\). 代码: #include<map> #include<set> #include<…

Keen On Everything But Triangle 题目传送门 解题思路 利用主席树求区间第k小,先求区间内最大的值,再求第二大,第三大--直到找到连续的三个数可以构成一个三角形.因为对于一组数,如果不能构成三角形,就小的就是斐波那契数列,因为数的范围在10^9内,所以不会超过50个数,也就是说,我们之间这样暴力地查询,查询次数不会超过50,肯定能找到结果. 代码如下 #include <bits/stdc++.h> #define INF 0x3f3f3f3f using nam…

题意: 给定一个数列,每次询问一个区间,问这个区间中的值可组成的周长最大的三角形的周长. 题解: 定理1:给定一些值,这些值中组成边长最大的三角形的三条边的大小排名一定是连续的. 证明:假如第k大,第k+1大,第k+2+b(b>0)大的三条边组成了一个边长最大的三角形,那么较小的两条边加起来长度大于第三边,又因为第k+2大的边比第k+2+b大的边长,因此把第k+2+b大的边换成第k+2大的边组成的三角形边长一定比原来大,矛盾. 定理2:如果三角形边长被限制为1e9以内的正整数,那么如果某组值存在…

传送门:http://acm.hdu.edu.cn/showproblem.php?pid=6300 Triangle Partition Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 132768/132768 K (Java/Others)Total Submission(s): 2964    Accepted Submission(s): 1474Special Judge Problem Description Chia…

题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=6601 Description N sticks are arranged in a row, and their lengths are a1,a2,...,aN. There are Q querys. For i-th of them, you can only use sticks between li-th to ri-th. Please output the maximum circu…

http://acm.hdu.edu.cn/showproblem.php?pid=6601 首先要贪心地想,题目要最长的边长,那么要怎么构造呢?在一段连续的区间里面,一定是拿出最长的三根出来比,这样一定是最大的(废话).而且假如组成三角形失败的话最长的那根这次就没有用了. 考虑临界情况,也就是刚刚好不能组成三角形的时候,要在1e9内尽可能地安排多的棒子,那就不妨设为:1,1,2,3,5,8--也就是斐波那契数列.可以打出来发现在43项左右的时候已经接近1e9了. 也就是每个区间真正有用的只是最…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=6601 题意是说用给定区间内的数字组成周长最大的三角形. 大致做法就是求区间第1大,第2大和第3大然后判断是否满足,不满足再求第4大,第5大..... 原本以为复杂度爆炸,结果想想发现最坏的情况只是斐波那契的样子,每个区间也不会很大. 求区间第i大就套了个主席树 #include <algorithm> #include<iostream> #include <cstdio>…

题目传送门//res tp hdu 目的 对长度为n的区间,给定q个子区间,求其元素能构成三角形的最大周长.有多组测试. n 1e5 q 1e5 ai [1,1e9] (i∈[1,n]); 数据结构 划分树 分析 需在不超过O(logn)的时间内完成一次查询 若一个数列不能构成三角形,则其为斐波那契数列.斐列不超过50项即可达到1e9,故每次只需查询区间的前k大即可,不超过50次询问,即可得到该数列是否能构成三角形 划分树的单次询问第k小/大为logn #include<iostream> #…

Problem Description N sticks are arranged in a row, and their lengths are a1,a2,...,aN. There are Q querys. For i-th of them, you can only use sticks between li-th to ri-th. Please output the maximum circumference of all the triangles that you can ma…

题意:给定一个长为n的序列,有q次询问,每次询问[l,r]这段区间内挑三个数,能组成的三角形的最大周长,无解输出-1 n,q<=1e5,a[i]<=1e9 思路:题解写法和我的不太一样 先说题解做法,显然最坏情况下是斐波那契数列的形式,大概是log2(1e9)项就没有-1了,所以维护一个可以取某一段中前50大的数字的数据结构,取出来之后sort看相邻3个取max即可 我的做法是用主席树把区间权值抠出来,树上二分权值,如果当前结点的右儿子的size>=3就必定是最优解,否则把右儿子中的所有…

#include<bits/stdc++.h> using namespace std; int main() { int n,q,l,r; while(cin>>n>>q) { vector<int> a(n); for(int i=0;i<n;i++) cin>>a[i]; while(q--) { cin>>l>>r; vector<int> b(r-l+1); for(int i=0;i<r…

有两个结论:1.排序后,答案一定是连续的三个数:2.当序列长度超过44一定有三个相同的数(因为即使该序列是斐波那契数列,此时也超过了1e9),然后用主席树等数据结构(略卡常,建议主席树)来维护前45大即可 1 #include<bits/stdc++.h> 2 using namespace std; 3 #define N 100005 4 #define mid (l+r>>1) 5 #define inf 1000000000 6 int V,n,m,k,x,y,a[N],b…

2019 Multi-University Training Contest 2 http://acm.hdu.edu.cn/contests/contest_show.php?cid=849 1005. Everything Is Generated In Equal Probability 考虑一个随机的排列的逆序对个数,显然对于两个数\(a,b\),他们位置是均匀排布的,也就是说有\(\frac{1}{2}\)的概率成为逆序对,并且是独立的. 所以一个长度为\(n\)的随机排列期望逆序对个…

2019 Multi-University Training Contest 2 A. Another Chess Problem B. Beauty Of Unimodal Sequence 题意 给一个序列,求下标字典序最小和字典序最大的,先增后减的序列. 解体过程 比赛时首先不知道字典序最小LIS怎么求. 试图枚举分界点.[解体的开始] 公无渡河,公竟渡河? 活鱼在摸鱼,rdc在划水,sdcgvhgj在水深火热. 做法 考虑字典序最小的LIS怎么求? 这是个经典问题,预处理前缀LIS后缀L…

Triangle 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5914 Description Mr. Frog has n sticks, whose lengths are 1,2, 3⋯n respectively. Wallice is a bad man, so he does not want Mr. Frog to form a triangle with three of the sticks here. He decides…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=4324 Triangle LOVE Description Recently, scientists find that there is love between any of two people. For example, between A and B, if A don’t love B, then B must love A, vice versa. And there is no pos…

Triangle Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 0    Accepted Submission(s): 0 Problem Description Mr. Frog has n sticks, whose lengths are 1,2, 3⋯n respectively. Wallice is a bad man,…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5914 Problem Description Mr. Frog has n sticks, whose lengths are 1,2, 3⋯n respectively. Wallice is a bad man, so he does not want Mr. Frog to form a triangle with three of the sticks here. He decides t…

hdu 3304 Interesting Yang Yui Triangle 题意: 给出P,N,问第N行的斐波那契数模P不等于0的有多少个? 限制: P < 1000,N <= 10^9 思路: lucas定理. 假设: n = a[k]*p^k + a[k-1]*p^(k-1) + ... + a[1]*p + a[0] m = b[k]*p^k + b[k-1]*p^(k-1) + ... + b[1]*p + b[0] 则: C(n,m) = pe(i=0~k,C(a[i],b[i])…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4483 题意:给出一个(n+1)*(n+1)的格子.在这个格子中存在多少个三角形? 思路:反着想,所有情况减去不是三角形的.下面计算不是三角形的. (1)我们用C(n,m)表示组合数.考虑共线,一共有C((n+1)*(n+1),3)种情况.然后,要减去共线的情况.首先,三个点在同一行或者同一列,这种情况有2*(n+1)*C(n+1,3):最后就是斜着共线的情况: (2)对于斜着共线的情况,我们可以枚举…

The Rascal Triangle Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 243    Accepted Submission(s): 192 Problem Description The Rascal Triangle definition is similar to that of the Pascal Triangl…

Problem Description Recently, scientists find that there is love between any of two people. For example, between A and B, if A don't love B, then B must love A, vice versa. And there is no possibility that two people love each other, what a crazy wor…

---恢复内容开始--- Heron and His Triangle Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 2543    Accepted Submission(s): 1060 Problem Description A triangle is a Heron’s triangle if it satisfies th…

Triangle LOVE Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1707    Accepted Submission(s): 729 Problem Description Recently, scientists find that there is love between any of two people. For…

Triangle Partition Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 132768/132768 K (Java/Others)Total Submission(s): 304    Accepted Submission(s): 170Special Judge Problem Description Chiaki has 3n points p1,p2,…,p3n. It is guaranteed that n…

Problem Description After Xiaoteng took a math class, he learned a lot of different shapes, but Xiaoteng's favorite triangle is because he likes stable shapes, just like his style. After the Xiaoxun knew it, he wanted to give a triangle as a gift to…

6300.Triangle Partition 这个题就是输出组成三角形的点的下标. 因为任意三点不共线,所以任意三点就可以组成三角形,直接排个序然后输出就可以了. 讲道理,没看懂官方题解说的啥... 官方题解: 求个凸包,然后选择凸包一条边AB,然后找个和AB夹角最小的点C,把ABC当做一个三角形删掉即可.这样做个n次,显然这样求出来的三角形们是合法的. 代码: //1003-6300-三角形水题 #include<iostream> #include<cstdio> #incl…

Triangle LOVE Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 3603    Accepted Submission(s): 1416 Problem Description Recently, scientists find that there is love between any of two people. Fo…

Given a triangle field and a rope of a certain length (Figure-1), you are required to use the rope to enclose a region within the field and make the region as large as possible. Input The input has several sets of test data. Each set is one line cont…