B题 思路 因为 \[ x=\sum\limits_{k=1}^{n}ka_k\\ y=\sum\limits_{k=1}^{n}ka_{k}^{2} \] 我们设交换前和交换后的这两个等式的值设为\(x_1,y_1,x_2,y_2\),现在我们开始愉快的推公式 \[ \begin{aligned} &x_1-x_2=(i-j)(a_i-a_j)&\\ &y_1-y_2=(i-j)(a_i^2-a_j^2)&\\ \Rightarrow &\frac{y1-y2}{…

Doki Doki Literature Club Time Limit: 1 Second      Memory Limit: 65536 KB Doki Doki Literature Club! is a visual novel developed by Team Salvato. The protagonist is invited by his childhood friend, Sayori, to join their high school's literature club…

我是铁牌选手 这次比赛非常得爆炸,可以说体验极差,是这辈子自己最脑残的事情之一. 天时,地利,人和一样没有,而且自己早早地就想好了甩锅的套路. 按理说不开K就不会这么惨了啊,而且自己也是毒,不知道段错误也可以是MLE,而且我的内存就是卡了那么一点点,在比赛紧张的状态下人也变傻了吧. 这次的题目难度是两边到中间一次递增的,但是我也不懂榜怎么会那样  A Peak Time Limit: 1 Second      Memory Limit: 65536 KB A sequence of  inte…

传送门 题意: 给出一个序列,你可以将任意一个数移到最前面: 求最少需要移动多少次,可以是此序列变成非递减序列: 思路: 定义 (ai,aj) 为逆序对 ( i < j , ai > aj ), 求出 aj 的最大值,用变量 curMax 存储: 遍历一遍数组,求解 ans: 对于∀ i ∈[1,n] ①如果 ai < curMax , ans++; ②如果 ai == curMax , 那么需要特殊判断: (2.1)如果 ai 之前不曾出现比 curMax 大的数,不需要移动: (2.…

http://acm.zju.edu.cn/onlinejudge/showContestProblems.do?contestId=392 E:Sequence in the Pocket 思路:从后往前判断在不在应该在的位置,如果不在则需要放到最前面,通过cnt控制当前的数 比较 排好序的数组的数. code: #include<bits/stdc++.h> using namespace std; #define LL long long #define INF 2000000000 #…

Heap Partition Time Limit: 2 Seconds      Memory Limit: 65536 KB      Special Judge A sequence S = {s1, s2, ..., sn} is called heapable if there exists a binary tree T with n nodes such that every node is labelled with exactly one element from the se…

What Kind of Friends Are You? Time Limit: 1 Second      Memory Limit: 65536 KB Japari Park is a large zoo home to extant species, endangered species, extinct species, cryptids and some legendary creatures. Due to a mysterious substance known as Sands…

Lucky 7 Time Limit: 1 Second      Memory Limit: 65536 KB BaoBao has just found a positive integer sequence  of length  from his left pocket and another positive integer  from his right pocket. As number 7 is BaoBao's favorite number, he considers a p…

CONTINUE...? Time Limit: 1 Second      Memory Limit: 65536 KB      Special Judge DreamGrid has  classmates numbered from  to . Some of them are boys and the others are girls. Each classmate has some gems, and more specifically, the -th classmate has …

King of Karaoke Time Limit: 1 Second      Memory Limit: 65536 KB It's Karaoke time! DreamGrid is performing the song Powder Snow in the game King of Karaoke. The song performed by DreamGrid can be considered as an integer sequence , and the standard…