题目链接:http://codeforces.com/contest/675/problem/C 给你n个bank,1~n形成一个环,每个bank有一个值,但是保证所有值的和为0.有一个操作是每个相邻的bank之间可以转钱,让你用最少的操作使每个bank的值为0. 一开始没什么思路,看了一下别人的题解,果然还是还是native... 要是让操作次数变少,首先划分和为0的区间个数要尽量多,比如一个区间的长度为k,那么他操作次数为k - 1,所以总的操作次数就是(n - 区间的个数). 那么要算出区…

C. Money Transfers 题目连接: http://www.codeforces.com/contest/675/problem/C Description There are n banks in the city where Vasya lives, they are located in a circle, such that any two banks are neighbouring if their indices differ by no more than 1. Al…

题目链接: http://www.codeforces.com/contest/675/problem/C 题意: 给一个数组,每个数与他相邻的数相连,第一个与最后一个相连,每个数的数值可以左右移动,问最少的移动次数使所有的数都为零. 题解: 把数组分成若干个部分,每个部分和都为0,每部分最多移动len-1,这样分的越多,得到的结果就越优. #include<iostream> #include<cstdio> #include<cstring> #include<…

B. Restoring Painting 题目连接: http://www.codeforces.com/contest/675/problem/B Description Vasya works as a watchman in the gallery. Unfortunately, one of the most expensive paintings was stolen while he was on duty. He doesn't want to be fired, so he h…

A. Infinite Sequence 题目连接: http://www.codeforces.com/contest/675/problem/A Description Vasya likes everything infinite. Now he is studying the properties of a sequence s, such that its first element is equal to a (s1 = a), and the difference between…

Galya is playing one-dimensional Sea Battle on a 1 × n grid. In this game a ships are placed on the grid. Each of the ships consists of b consecutive cells. No cell can be part of two ships, however, the ships can touch each other. Galya doesn't know…

Beru-taxi 题目链接: http://codeforces.com/contest/706/problem/A Description Vasiliy lives at point (a, b) of the coordinate plane. He is hurrying up to work so he wants to get out of his house as soon as possible. New app suggested n available Beru-taxi…

Codeforces Round #575 (Div. 3) 这个div3打的太差了,心态都崩了. B. Odd Sum Segments B 题我就想了很久,这个题目我是找的奇数的个数,因为奇数想分成x个奇数,那么这个x肯定是一个奇数, 偶数同理,如果一个偶数想分成y个奇数,那么这个y肯定是一个偶数. 所以数奇数的个数,如果奇数有x个,x是偶数,那么k一定是一个偶数,如果x是一个奇数,那么k肯定是一个奇数. 输出也比较简单,因为奇数要分成奇数个,所以可以前面每组都是含有一个奇数,最后肯定会有奇…

A. Uncowed Forces Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/604/problem/A Description Kevin Sun has just finished competing in Codeforces Round #334! The round was 120 minutes long and featured five problems with maxi…

Problems     # Name     A Infinite Sequence standard input/output 1 s, 256 MB    x3509 B Restoring Painting standard input/output 1 s, 256 MB    x2519 C Money Transfers standard input/output 1 s, 256 MB    x724 D Tree Construction standard input/outp…

数学 A - Infinite Sequence 等差数列,公差是0的时候特判 #include <bits/stdc++.h> typedef long long ll; const int N = 1e5 + 5; int main() { int a, b, c; scanf ("%d%d%d", &a, &b, &c); bool flag = true; if (c == 0) { if (a == b) { flag = true; }…

题目链接: http://www.codeforces.com/contest/675/problem/E 题意: 对于第i个站,它与i+1到a[i]的站有路相连,先在求所有站点i到站点j的最短距离之和(1<=i<j<=n) 题解: 这种所有可能都算一遍就会爆的题目,有可能是可以转化为去求每个数对最后答案的贡献,用一些组合计数的方法一般就可以很快算出来. 这里用dp[i]表示第i个站点到后面的所有站的最短距离之和,明显,i+1到a[i]的站,一步就可以到,对于后面的那些点,贪心一下,一定…

题目链接: http://codeforces.com/contest/675/problem/D 题意: 给你一系列点,叫你构造二叉搜索树,并且按输入顺序输出除根节点以外的所有节点的父亲. 题解: n有10^5,如果直接去建树,最会情况会O(n^2)t掉. 因此我们需要利用一些二叉搜索树的性质: 对于当前输入节点v,找出已经输入的最大的l和最小的r使得l<v<r. 由于输入v之前l和r中间是没有数的,所以l和r必定为祖先和后代的关系,如果不是的话,就会导致l和r中间还有数(l和r的公共祖先)…

题目链接:http://codeforces.com/problemset/problem/675/D 给你一个如题的二叉树,让你求出每个节点的父节点是多少. 用set来存储每个数,遍历到a[i]的时候查找比a[i]大的数的位置,然后插入,而父亲就是刚好比a[i]小的数或刚好大的数. 然后讨论是哪一个数. 比如给你3 1 2 ,如图 1的父亲是3 ,2的父亲是1. 那我其实只要找左边或右边出现最晚的数就行了,用pair的first表示a[i],second表示出现的顺序i. #include <…

http://codeforces.com/contest/675/problem/E 题目大意:有n个车站,每个车站只能买一张票,这张票能从i+1到a[i].定义p[i][j]为从i到j所需要买的最小票数.问sigma(p)的和是多少. 思路:感觉我的dp定义能力还是太弱了啊,我刚开始还定义成dp[i]表示1~i-1到i所需要的最小花费和,后来发现这样子我转移不了啊!! 于是重新定义dp[i]表示从i出发到i+1~n所需要的最小票数,然后这样定义就能很好的解决问题啦.然后我们每次贪心的选取j…

E. Trains and Statistic 题目连接: http://www.codeforces.com/contest/675/problem/E Description Vasya commutes by train every day. There are n train stations in the city, and at the i-th station it's possible to buy only tickets to stations from i + 1 to a…

D. Tree Construction 题目连接: http://www.codeforces.com/contest/675/problem/D Description During the programming classes Vasya was assigned a difficult problem. However, he doesn't know how to code and was unable to find the solution in the Internet, so…

Tree Construction Problem's Link ---------------------------------------------------------------------------- Mean: 给定n个数,按照构造Binary Search Tree的方式来构造BST树,按顺序输出每一个非root结点的父节点的值. analyse: 构造BST树最坏情况下时间复杂度为O(n),肯定会超时. 注意到只需要输出结点的父节点的值,不需要真的构造BST树. 插到第i…

Vasya works as a watchman in the gallery. Unfortunately, one of the most expensive paintings was stolen while he was on duty. He doesn't want to be fired, so he has to quickly restore the painting. He remembers some facts about it. The painting is a…

Vasya likes everything infinite. Now he is studying the properties of a sequence s, such that its first element is equal to a (s1 = a), and the difference between any two neighbouring elements is equal to c (si - si - 1 = c). In particular, Vasya won…

弱到只会写div2的A题... 题面: A. Infinite Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya likes everything infinite. Now he is studying the properties of a sequence s, such that its fi…

题意:给你n个数字,第一个点作为根节点,然后每次插入一个节点,构建一棵平衡二叉树,并输出插入节点后该节点的父节点的值 #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> #include <vector> #include <queue> #include <stack> #in…

A. Wizards' Duel Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/591/problem/A Description Harry Potter and He-Who-Must-Not-Be-Named engaged in a fight to the death once again. This time they are located at opposite ends of…

A. LCM Challenge 题目连接: http://www.codeforces.com/contest/235/problem/A Description Some days ago, I learned the concept of LCM (least common multiple). I've played with it for several times and I want to make a big number with it. But I also don't wa…

B. Testing Robots Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://www.codeforces.com/contest/606/problem/B Description The Cybernetics Failures (CF) organisation made a prototype of a bomb technician robot. To find the possible problems it was de…

A. Magic Spheres Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://www.codeforces.com/contest/606/problem/A Description Carl is a beginner magician. He has a blue, b violet and c orange magic spheres. In one move he can transform two spheres of the…

A. Two Substrings Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/A Description You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB" and "…

A. Even Odds Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/318/problem/A Description Being a nonconformist, Volodya is displeased with the current state of things, particularly with the order of natural numbers (natural n…

A. Two Bases Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/602/problem/A Description After seeing the "ALL YOUR BASE ARE BELONG TO US" meme for the first time, numbers X and Y realised that they have different bases,…

A. Calculating Function Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/486/problem/A Description For a positive integer n let's define a function f: f(n) =  - 1 + 2 - 3 + .. + ( - 1)nn Your task is to calculate f(n) for a…