虚拟参赛的时候没想到是线段树,看到很多人都过了,也蛮着急的. 首先用二分+线段树的方法更新DP[i]:它表示以A[i]为结尾可以最前到哪个位置: 再用线段树计算ans[i]:它表示当前i个A元素可以最少分成多少个pieces,ans[i]=1+min(ans[j]),dp[i]-1<=j<=i-L. over. #define N 100000+5 int a[N],dp[N],Ans[N]; struct segment { int l,r; int Min,Max,ans; } seg[*…

Codeforces VP/补题小记 1149 C. Tree Generator 给你一棵树的括号序列,每次交换两个括号,维护每次交换之后的直径. ​ 考虑括号序列维护树的路径信息和,是将左括号看做 \(-1\) ,右括号看做 \(1\) ,那么一段竖直向上的路径可以表示为括号序列的一个区间和,一段竖直向下的路径可以看做括号序列的一个区间和的相反数.我们要维护的是树的直径,也就是一段连续的和减去紧随其后的一段连续的差.具体来说就是 \[ \max_{\forall [l,r]}\{\sum_{…

Prison Transfer Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description The prison of your city has n prisoners. As the prison can't accommodate all of them, the city mayor has decided to transfer c of t…

题目地址:http://codeforces.com/contest/459/problem/C C. Pashmak and Buses time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Recently Pashmak has been employed in a transportation company. The com…

鉴于Codeforces和atcoder上有很多神题,即使发呆了一整节数学课也是肝不出来,所以就记录一下. AGC033B LRUD Game 只要横坐标或者纵坐标超出范围就可以,所以我们只用看其中一维就可以了. 我们又知道,如果先手想要让它从左边出去,那么先手就会一直Left,后手就会一直Right. 所以枚举四种情况(L,R,U,D)就可以了. AGC033C Removing Coins 首先我们考虑链的情况,如果选的是端点,那么有一个点没有硬币,如果选的不是端点,那么有两个点没有硬币.所…

B - Save the problem! CodeForces - 867B 这个题目还是很简单的,很明显是一个构造题,但是早训的时候脑子有点糊涂,想到了用1 2 来构造, 但是去算这个数的时候算错了... 用1 2 来构造 可以先枚举一些数来找找规律. 1 1 2 2 3 1 1 1    2 1 1 4 .... 可以发现每一个数都是 n/2+1 的可能, 所以反过来推过去就是 (s-1)*2  或者(s-1)*2+1 这个(s-1)*2+1的答案才是正确答案 因为 这个s可以==1 #i…

Squats Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Pasha has many hamsters and he makes them work out. Today, n hamsters (n is even) came to work out. The hamsters lined up and each hamster e…

Marathon Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Valera takes part in the Berland Marathon. The marathon race starts at the stadium that can be represented on the plane as a square whose…

Valera and X Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Valera is a little boy. Yesterday he got a huge Math hometask at school, so Valera didn't have enough time to properly learn the Engli…

Inna and Alarm Clock Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Inna loves sleeping very much, so she needs n alarm clocks in total to wake up. Let's suppose that Inna's room is a 100 × 100 …