原题链接 题意简述 给出一个由个数构成的环,每次可以选择一个位置并从这个数起顺时针依次对每个数-1,-2,-3,-,-n.问能否将所有数全变为0. 分析 考虑一次操作对环带来了什么影响. (在后加一个来表示数环) -> -> 差分后: -> -> 可以看到,一次操作相当于对差分数列(或者说是差分环)的一个位置加上n-1,剩下的位置减去1.那么只要检查原环的差分数列能否全变为0,并且此时和也为0就行了. 对每一个位置的计算复杂度为,总时间复杂度为. 实现 每次操作会使和减少 ,那么总…

B - Boxes 题目连接: http://agc010.contest.atcoder.jp/tasks/agc010_b Description There are N boxes arranged in a circle. The i-th box contains Ai stones. Determine whether it is possible to remove all the stones from the boxes by repeatedly performing the…

AGC010 A - Addition 如果所有数加起来是偶数那么一定可以,否则不行 #include <bits/stdc++.h> #define fi first #define se second #define pii pair<int,int> #define mp make_pair #define pb push_back #define space putchar(' ') #define enter putchar('\n') #define eps 1e-10…

安装Fedora 24在试用虚拟机时发现无法ping通外网. 我傻傻地以为是软件问题. 问题描述: 尝试ping程序来测试网络连通性: (我之前也是ping百度,后来在为了少打字百度了一些比较短的域名. 比如: "to." , "g.cn" , "j.mp" 等等.) (http://wenku.baidu.com/link?url=oSb0I5xzI1UBhU3aKTXoWll7PYaIm0zNiORJbx_h6PlT-bURWFOCXkW9W…

 省赛B题....手写链表..其实很简单的.... 比赛时太急了,各种手残....没搞出来....要不然就有金了...注:对相邻的元素需要特判..... Problem B Boxes in a Line You have n boxes in a line on the table numbered 1~n from left to right. Your task is to simulate 4 kinds of commands: 1 X Y: move box X to the lef…

C. Inna and Candy Boxes   Inna loves sweets very much. She has n closed present boxes lines up in a row in front of her. Each of these boxes contains either a candy (Dima's work) or nothing (Sereja's work). Let's assume that the boxes are numbered fr…

boxes [英][bɒksɪz][美][bɑ:ksɪz] n.盒( box的名词复数 ); 一盒; 电视; 小亭; v.把…装入盒[箱,匣]中( box的第三人称单数 ); 拳击;   以上结果来自金山词霸…

B. Candy Boxes Problem's Link:   http://codeforces.com/contest/488/problem/B Mean: T题目意思很简单,不解释. analyse: 这道题还是很有意思的,需要考虑到各种情况才能AC. 解这个题目之前,首先要推出两条式子 x4=3x1 4x1=x2+x3 然后就是分类讨论,枚举各种情况就可. Time complexity: O(1) Source code:  // Memory Time // 1347K 0MS…

题目来源:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=3&page=show_problem&problem=39  Stacking Boxes  Background Some concepts in Mathematics and Computer Science are simple in one or two dimensions but become…

9.10 You have a stack of n boxes, with widths w., heights hir and depths drThe boxes cannot be rotated and can only be stacked on top of one another if each box in the stack is strictly larger than the box above it in width, height, and depth. Implem…