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…

如果一开始就满足题意,不用变换. 否则,如果对一对ai,ai+1用此变换,设新的gcd为d,则有(ai - ai+1)mod d = 0,(ai + ai+1)mod d = 0 变化一下就是2 ai mod d = 0 2 ai+1 mod d = 0 也就是说,用两次变换之后,gcd至少扩大2倍,于是,最优方案就是我们将所有的奇数都变成偶数. 只需要找出所有奇数段,答案就是sigma([奇数段的长度/2]+(奇数段的长度 mod 2 ==1 ?)). #include<cstdio> #i…

E. Mike and Geometry Problem 题目连接: http://www.codeforces.com/contest/689/problem/E 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 to…

任意门:http://codeforces.com/contest/689/problem/E E. Mike and Geometry Problem time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Mike wants to prepare for IMO but he doesn't know geometry, so…

E. Mike and Geometry Problem time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Mike wants to prepare for IMO but he doesn't know geometry, so his teacher gave him an interesting geometry pro…

A. Mike and palindrome time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the s…

A. Mike and palindrome time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has a string s consisting of only lowercase English letters. He wants to change exactly onecharacter from the st…

B. Mike and strings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has n strings s1, s2, ..., sn each consisting of lowercase English letters. In one move he can choose a string si,…

传送门 Description Mike has n strings s1, s2, ..., sn each consisting of lowercase English letters. In one move he can choose a string si, erase the first character and append it to the end of the string. For example, if he has the string "coolmike"…

题目链接:传送门 题目大意:给你n个区间,求任意k个区间交所包含点的数目之和. 题目思路:将n个区间都离散化掉,然后对于一个覆盖的区间,如果覆盖数cnt>=k,则数目应该加上 区间长度*(cnt与k的组合数) ans=ans+(len*C(cnt,k))%mod; #include <iostream> #include <cstdio> #include <cstdlib> #include <cmath> #include <algorith…

Codeforces Round #410 (Div. 2) A B略..A没判本来就是回文WA了一次gg C.Mike and gcd problem 题意:一个序列每次可以把\(a_i, a_{i+1}\)换成\(a_i-a_{i+1},a_i+a_{i+1}\),最小次数使gcd不为1 题解: 玩一下发现: 奇数 奇数 \(\rightarrow\) 偶数 偶数 奇数 偶数 $ \rightarrow$ 奇数 奇数 \(\rightarrow\) 偶数 偶数 最后都变成偶数好像就是最优啊,…

题目传送门 /* 题意:对于长度为x的子序列,每个序列存放为最小值,输出长度为x的子序列的最大值 set+线段树:线段树每个结点存放长度为rt的最大值,更新:先升序排序,逐个添加到set中 查找左右相邻的位置,更新长度为r - l - 1的最大值,感觉线段树结构体封装不错! 详细解释:http://blog.csdn.net/u010660276/article/details/46045777 其实还有其他解法,先掌握这种:) */ #include <cstdio> #include &l…

题目传送门 /* 数论/暴力:找出第一次到a1,a2的次数,再找到完整周期p1,p2,然后以2*m为范围 t1,t2为各自起点开始“赛跑”,谁落后谁加一个周期,等到t1 == t2结束 详细解释:http://blog.csdn.net/u014357885/article/details/46044287 */ #include <cstdio> #include <algorithm> #include <cstring> #include <iostream…

题目传送门 /* 暴力:每次更新该行的num[],然后暴力找出最优解就可以了:) */ #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <string> using namespace std; ; const int INF = 0x3f3f3f3f; int a[MAXN][MAXN]; int num[MAXN];…

题目传送门 /* 字符串处理:回文串是串联的,一个一个判断 */ #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <string> using namespace std; ; const int INF = 0x3f3f3f3f; char s[MAXN]; bool check(int x, int y) { for…

A. Mike and palindrome time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the s…

A. Mike and palindrome time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the s…

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 if…

A 题意:问你恰好修改一个字符,能不能使得字符串变成回文串 题解:显然直接for一遍,如果长度为偶数,那么不一样的必须是1个:如果长度为奇数,那么不一样的也可以是0个 #include<bits/stdc++.h> using namespace std; string s; int main(){ cin>>s; int tmp = 0; for(int i=0;i<s.size();i++){ if(s[i]!=s[s.size()-1-i]) tmp++; } if(t…

 B. Mike and Fun Time Limit: 20 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/548/problem/A Description Mike and some bears are playing a game just for fun. Mike is the judge. All bears except Mike are standing in an n × m grid, there'…

 A. Mike and Fax Time Limit: 20 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/548/problem/A Description While Mike was walking in the subway, all the stuff in his back-bag dropped on the ground. There were several fax messages among th…

C. Mike and Chocolate Thieves 题目连接: http://www.codeforces.com/contest/689/problem/C Description Bad news came to Mike's village, some thieves stole a bunch of chocolates from the local factory! Horrible! Aside from loving sweet things, thieves from t…

B. Mike and Shortcuts 题目连接: http://www.codeforces.com/contest/689/problem/B Description Recently, Mike was very busy with studying for exams and contests. Now he is going to chill a bit by doing some sight seeing in the city. City consists of n inter…

A. Mike and Cellphone 题目连接: http://www.codeforces.com/contest/689/problem/A 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-fas…

B. Mike and Feet Time Limit: 20 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/547/problem/B Description Mike is the president of country What-The-Fatherland. There are n bears living in this country besides Mike. All of them are standi…

 A. Mike and Frog Time Limit: 20 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/547/problem/A Description Mike has a frog and a flower. His frog is named Xaniar and his flower is named Abol. Initially(at time 0), height of Xaniar is h1…

Description Mike has a string s consisting of only lowercase English letters. He wants to change exactly one character from the string so that the resulting one is a palindrome. A palindrome is a string that reads the same backward as forward, for ex…

D. Mike and distribution time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has always been thinking about the harshness of social inequality. He's so obsessed with it that sometimes it…

B. Mike and strings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mike has n strings s1, s2, ..., sn each consisting of lowercase English letters. In one move he can choose a string si,…

D. Mike and Feet time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Mike is the president of country What-The-Fatherland. There are n bears living in this country besides Mike. All of them are…