Description Let's consider one interesting word game. In this game you should transform one word into another through special operations. Let's say we have word w, let's split this word into two non-empty parts x and y so, that w = xy. A split operat…

Word Cut Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 176B Description Let's consider one interesting word game. In this game you should transform one word into another through specia…

题目链接:http://acm.uestc.edu.cn/#/problem/show/1217 题目大意就是求一个序列里面长度为m的递增子序列的个数. 首先可以列出一个递推式p(len, i) = sum(p(len-1, j)) (a[j] < a[i]) p(len, i)表示以第i个结尾的长度为len的子序列的个数. 但是如果按照递增子序列的思想,然后直接弄的话,复杂度是n*m*n的. 如果需要优化的话,可以优化的地方就是那个求sum的过程. 把p数组映射到树状数组,那么求和的过程就能在…

Description "Well, it seems the first problem is too easy. I will let you know how foolish you are later." feng5166 says. "The second problem is, given an positive integer N, we define an equation like this:   N=a[1]+a[2]+a[3]+...+a[m];   a…

Word Cut 题目连接: http://codeforces.com/problemset/problem/176/C Description Let's consider one interesting word game. In this game you should transform one word into another through special operations. Let's say we have word w, let's split this word in…

B. Word Cut   Let's consider one interesting word game. In this game you should transform one word into another through special operations. Let's say we have word w, let's split this word into two non-empty parts x and y so, that w = xy. A split oper…

http://codeforces.com/contest/676 在allzysyz学弟和hqwhqwhq的邀请下,打了我的第三场CF... 毕竟在半夜..所以本来想水到12点就去睡觉的...结果一下次过了三题,发现第四题是个bfs,就打到了12:30....BC貌似是没有了,不知道后面还会不会有,最近就打CF为主吧.. A题: http://codeforces.com/problemset/problem/676/A 应该算是比较水吧.没有什么坑点.直接枚举最大值在最左最右侧和最小值在最左…

题目链接:http://codeforces.com/problemset/problem/590/A 题目大意是给一个串,头和尾每次变换保持不变. 中间的a[i]变成a[i-1],a[i],a[i+1]的中位数,而且此题串是01串. 对于01串 0 0 0中位数是0 0 0 1中位数是0 0 1 1中位数是1 1 1 1中位数是1 所以 1.串中有两个相邻以上的0或者1是保持不变的. 2.会变的只有是两个1中间的0或者两个0中间的1. 但是到这里的话,虽然证明了肯定能变成稳定态,就算把相同数字…

题目链接:http://codeforces.com/problemset/problem/601/A 题目大意是有铁路和陆路两种路,而且两种方式走的交通工具不能在中途相遇. 此外,有铁路的地方肯定没有陆路. 这种情况下就会有一个结论,就是至少有一种交通可以直接1到n. 这样只需要对另一种跑一个最短路就OK了. 代码: #include <iostream> #include <cstdio> #include <cstdlib> #include <cmath&…

Description 题库链接 给你两个字符串 \(S\) 和 \(T\) ,准许你 \(k\) 次操作,每次将字符串左右分成两个非空的部分,再交换位置,问你有多少种不同的操作方法将 \(S\) 串变为 \(T\) 串. \(1\leq k\leq 100000, 1\leq |S|=|T|\leq 1000\) Solution 容易发现不论经过多少次操作,其操作后的字符串一定是在原字符串上截开两段再拼接而成. 所以不妨记 \(f_{i,j}\) 为操作 \(i\) 次后在 \(j\) 处截…