题 Today, Wet Shark is given n integers. Using any of these integers no more than once, Wet Shark wants to get maximum possible even (divisible by 2) sum. Please, calculate this value for Wet Shark. Note, that if Wet Shark uses no integers from the n …

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output There are b blocks of digits. Each one consisting of the same n digits, which are given to you in the input. Wet Shark must choose exactly one d…

题 There are n sharks who grow flowers for Wet Shark. They are all sitting around the table, such that sharks i andi + 1 are neighbours for all i from 1 to n - 1. Sharks n and 1 are neighbours too. Each shark will grow some number of flowers si. For i…

题 题意 1000*1000的格子里,给你n≤200 000个点的坐标,求有多少对在一个对角线上. 分析 如果求每个点有几个共对角线的点,会超时. 考虑到对角线总共就主对角线1999条+副对角线1999条,我们可以求每个对角线有几对点. 同一条主对角线上的元素有a[i]个,就有C(a[i],2)对点: 同一条副对角线上的元素有b[i]个,就有C(b[i],2)对点. 读入x和y后, x+y相同的就在同一副对角线,x+y范围是(2,2000), x-y相同的就是同一主对角线,x-y范围是(-999…

[codeforces 415D]Mashmokh and ACM 题意:美丽数列定义:对于数列中的每一个i都满足:arr[i+1]%arr[i]==0 输入n,k(1<=n,k<=2000),问满足[数列长度是k && 数列中每一个元素arr[i]在1~n之间 && 数列中元素可以重复]的数列有多少个?结果对10^9+7取余 解题思路:dp[i][j]表示长度是j,最后一位是i的种数 if(kk%i==0) dp[kk][j+1]+=dp[i][j] #inc…

A. Wet Shark and Odd and Even time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Today, Wet Shark is given n integers. Using any of these integers no more than once, Wet Shark wants to get ma…

[题目链接]:http://codeforces.com/problemset/problem/746/E [题意] 你有n张卡片,上面写着不同的数字; 然后另外一个人有m张上面写着不同的数字的卡片:卡片上的数字从1..m; 你可以和另外一个人交换卡片; 问你最少的交换次数; 使得你的n张卡片里面,卡片上的数字为奇数的和卡片上的数字为偶数的张数相同. 且这n张卡片不能有相同的数字; [题解] 首先考虑去重的工作; 在去重之前;先算出; 原来的n张卡片里面,卡片上的数字是奇数的数字个数odd; 然…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output After Vitaly was expelled from the university, he became interested in the graph theory. Vitaly especially liked the cycles of an odd length in w…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Vanya is doing his maths homework. He has an expression of form , where x1, x2, -, xn are digits from 1 to 9, and sign represents either a plus '…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output As behooves any intelligent schoolboy, Kevin Sun is studying psycowlogy, cowculus, and cryptcowgraphy at the Bovinia State University (BGU) under…