Educational Codeforces Round 23 B. Makes And The Product
2 seconds
256 megabytes
standard input
standard output
After returning from the army Makes received a gift — an array a consisting of n positive integer numbers. He hadn't been solving problems for a long time, so he became interested to answer a particular question: how many triples of indices (i, j, k)(i < j < k), such that ai·aj·ak is minimum possible, are there in the array? Help him with it!
The first line of input contains a positive integer number n (3 ≤ n ≤ 105) — the number of elements in array a. The second line contains n positive integer numbers ai (1 ≤ ai ≤ 109) — the elements of a given array.
Print one number — the quantity of triples (i, j, k) such that i, j and k are pairwise distinct and ai·aj·ak is minimum possible.
4
1 1 1 1
4
5
1 3 2 3 4
2
6
1 3 3 1 3 2
1
In the first example Makes always chooses three ones out of four, and the number of ways to choose them is 4.
In the second example a triple of numbers (1, 2, 3) is chosen (numbers, not indices). Since there are two ways to choose an element 3, then the answer is 2.
In the third example a triple of numbers (1, 1, 2) is chosen, and there's only one way to choose indices.
题意:
给一串数字,在其中选三个数字,使得这三个数字的乘积最小,问有多少个这样的组合
思路:
直接排序乘积最小那么这三个数字必定是最小的三个,又因为数字可能相同,会产成不同结果的情况一共有三种:
1.三个数字都相同 。
2.第一个和第二个不同,第二个与第三个相同。
3.第二个和第三个不同。
实现代码:
#include<iostream>
#include<algorithm>
#include<map>
using namespace std;
#define ll long long
map<ll,ll>mp;
int main()
{
ll m,i,a[];
cin>>m;
for(i=;i<m;i++){
cin>>a[i];
mp[a[i]]++;}
sort(a,a+m);
ll sum = ;
if(a[]==a[]&&a[]==a[]){
ll num = mp[a[]];
sum = (num*(num-)*(num-))/;
}
if(a[]!=a[]){
ll num = mp[a[]];
sum = num;
}
if(a[]!=a[]&&a[]==a[]){
ll num = mp[a[]];
// num = 99999;
sum = (num*(num-))/;
} cout<<sum<<endl;
}
Educational Codeforces Round 23 B. Makes And The Product的更多相关文章
- Educational Codeforces Round 23 E. Choosing The Commander trie数
E. Choosing The Commander time limit per test 2 seconds memory limit per test 256 megabytes input st ...
- Educational Codeforces Round 23.C
C. Really Big Numbers time limit per test 1 second memory limit per test 256 megabytes input standar ...
- Educational Codeforces Round 23 F. MEX Queries 离散化+线段树
F. MEX Queries time limit per test 2 seconds memory limit per test 256 megabytes input standard inpu ...
- Educational Codeforces Round 23 D. Imbalanced Array 单调栈
D. Imbalanced Array time limit per test 2 seconds memory limit per test 256 megabytes input standard ...
- Educational Codeforces Round 23 C. Really Big Numbers 暴力
C. Really Big Numbers time limit per test 1 second memory limit per test 256 megabytes input standar ...
- Educational Codeforces Round 23 补题小结
昨晚听说有教做人场,去补了下玩. 大概我的水平能做个5/6的样子? (不会二进制Trie啊,我真菜) A. 傻逼题.大概可以看成向量加法,判断下就好了. #include<iostream> ...
- Educational Codeforces Round 23
A题 分析:注意两个点之间的倍数差,若为偶数则为YES,否则为NO #include "iostream" #include "cstdio" #include ...
- Educational Codeforces Round 23 A-F 补题
A Treasure Hunt 注意负数和0的特殊处理.. 水题.. 然而又被Hack了 吗的智障 #include<bits/stdc++.h> using namespace std; ...
- Educational Codeforces Round 40千名记
人生第二场codeforces.然而遇上了Education场这种东西 Educational Codeforces Round 40 下午先在家里睡了波觉,起来离开场还有10分钟. 但是突然想起来还 ...
随机推荐
- Linux系列教程(五)——Linux常用命令之链接命令和权限管理命令
前一篇博客我们讲解了Linux文件和目录处理命令,还是老生常淡,对于新手而言,我们不需要完全记住命令的详细语法,记住该命令能完成什么功能,然后需要的时候去查就好了,用的多了我们就自然记住了.这篇博客我 ...
- Ajax获取 Json文件提取数据
摘自 Ajax获取 Json文件提取数据 1. json文件内容(item.json) [ { "name":"张国立", "sex":&q ...
- Linux下安装jdk+maven +git
Linux系统下的操作,一直不是很熟悉.作为一名java开发工程师,感到很惭愧.因此把自己的阿里云服务器安装环境相关的东西给记录下来,方便后续查阅. 本文所采用的Lin ...
- centos7.4下Jira6环境部署及破解操作记录(完整版)
废话不多说,以下记录了Centos7针对Jira6的安装,汉化,破解的操作过程,作为运维笔记留存. 0) 基础环境 192.168.10.212 Centos7.4 mysql 5.6 jdk 1.8 ...
- centos7下安装php+memcached简单记录
1)centos7下安装php 需要再添加一个yum源来安装php-fpm,可以使用webtatic(这个yum源对国内网络来说恐怕有些慢,当然你也可以选择其它的yum源) [root@nextclo ...
- mysql操作命令梳理(2)-alter(update、insert)
在mysql运维操作中会经常使用到alter这个修改表的命令,alter tables允许修改一个现有表的结构,比如增加或删除列.创造或消去索引.改变现有列的类型.或重新命名列或表本身,也能改变表的注 ...
- 分布式监控系统Zabbix-3.0.3-完整安装记录(1)
分布式监控系统Zabbix-3.0.3的安装记录 环境说明zabbix-server:192.168.1.30 #zabbix的服务端(若要监控本机,则需要配置本机的Zabbix agent, ...
- python基础学习笔记(二)
继续第一篇的内容,讲解,python的一些基本的东西. 注释 为了让别人能够更容易理解程序,使用注释是非常有效的,即使是自己回头再看旧代码也是一样. >>> #获得用户名: > ...
- 《Linux内核设计与实现》第五章学习笔记
<Linux内核设计与实现>第五章学习笔记 姓名:王玮怡 学号:20135116 一.与内核通信 在Linux中,系统调用是用户空间访问内核的唯一手段:除异常和陷入外,它们是内核 ...
- 《Linux内核分析》期终总结&《Linux及安全》期中总结
<Linux内核分析>期终总结&<Linux及安全>期中总结 [李行之 原创作品 转载请注明出处 <Linux内核分析>MOOC课程http://mooc. ...