C. Mike and gcd problem time limit per test: 2 seconds memory limit per test: 256 megabytes input: standard input output: standard output Mike has a sequence A = [a1, a2, ..., an] of length n. He considers the sequence B = [b1, b2, ..., bn] beautiful…

Mike and Geometry Problem 题目链接: http://acm.hust.edu.cn/vjudge/contest/121333#problem/I Description Mike wants to prepare for IMO but he doesn't know geometry, so his teacher gave him an interesting geometry problem. Let's define f([l, r]) = r - l + 1…

题目链接:http://codeforces.com/problemset/problem/798/C 题意:给你n个数,a1,a2,....an.要使得gcd(a1,a2,....an)>1,可以执行一次操作使ai,ai+1变为ai - ai + 1, ai + ai + 1.求出使得gcd(a1,a2,....an)>1所需要的最小操作数. 解题思路:首先,要知道如果能够实现gcd(a1,a2,....an)>1,那么a1~an肯定都是偶数(0也是偶数),所以我们的目的就是用最少的操…

题目意思:给出一个n个数的序列:a1,a2,...,an (n的范围[2,100000],ax的范围[1,1e9] ) 现在需要对序列a进行若干变换,来构造一个beautiful的序列: b1,b2, ..., bn,使得最大公约数 gcd(b1,b2,...,bn) > 1. 变换:  任意ai,ai+1 进行一次操作时,可以用 ai-ai+1, ai+ai+1 来替换. 问序列 a 构造成 序列 b ,使得gcd(b序列) > 1 的最小操作次数 题目解析: 首先,这个题目是肯定有解的,也…

题意: 给出一个数列,现在有一种操作,可以任何一个a[i],用a[i] – a[i+1]和a[i]+a[i+1]替代a[i]和a[i+1]. 问现在需要最少多少次操作,使得整个数列的gcd大于1. 思路: 经过思考后发现,除非所有的数的gcd已经大于1,那么就必须把全部数字变为偶数. 变数字的时候,必须从第一个不是偶数的数字开始变化,每次都从下标最小的为奇数的数字开始变化. 如果是奇数,奇数,那么显然经过一次就可以全部变为偶数: 如果是奇数,偶数,那么必须经过两次才能全部变成偶数. 这题实际是贪…

C. Bear and Different Names time limit per test:1 second memory limit per test:256 megabytes input:standard input output:standard output In the army, it isn't easy to form a group of soldiers that will be effective on the battlefield. The communicati…

Mike and Cellphone 题目链接: http://acm.hust.edu.cn/vjudge/contest/121333#problem/E Description While swimming at the beach, Mike has accidentally dropped his cellphone into the water. There was no worry as he bought a cheap replacement phone with an old…

离散化,树状数组,组合数学. 这题的大致思路和$HDU$ $5700$一样.都是求区间交的问题.可以用树状数组维护一下. 这题的话只要计算每一个$i$被统计了几次,假设第$i$点被统计了$ans[i]$次,累加和就是答案. $ans[i]$就是看$i$点之后有多少个区间右端点,假设有$m$个,那么$ans[i]$就等于$m$个里面选$k$个的方案数. 因为数据中$L$,$R$范围较大,所以需要先离散化,计算离散化之后的情况,然后再统计离散化之前的情况. #pragma comment(linke…

题目连接:http://codeforces.com/contest/798/problem/C C. Mike and gcd problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has a sequence A = [a1, a2, ..., an] of length n. He considers…

C. Mike and gcd problem http://www.cnblogs.com/BBBob/p/6746721.html #include<iostream> #include<cstdio> #include<string> #include<cstring> #include<algorithm> #include<cmath> using namespace std; ; int a[maxn]; int gcd(…