F. Video Cards time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Little Vlad is fond of popular computer game Bota-2. Recently, the developers announced the new add-on named Bota-3. Of course…

题目链接:http://codeforces.com/contest/731/problem/F 题意:有n个数,从里面选出来一个作为第一个,然后剩下的数要满足是这个数的倍数,如果不是,只能减小为他的倍数,否则就舍弃掉,然后把没有舍弃的数的值加起来,求和的最大值; 43 2 15 9 就拿这个来说,当拿3当做第一个数时结果是3+15+9=27因为2不是3的倍数:当拿2作为第一个数时,结果是2+2+14+8=26因为3,15,9都不是2的倍数,所以只能减小;同理...求最大的和; 我们可以记录每个…

http://codeforces.com/contest/731/problem/F 注意到一个事实,如果你要找一段区间中(从小到大的),有多少个数是能整除左端点L的,就是[L, R]这样.那么,很明显,把这个区间分段.分成[L, 2 * L - 1],因为这段区间中,都不大于等于L的两倍,这样就使得这段区间的贡献就是sum_number * L了. 就是中间有多少个数,每个数贡献一个L值.然后到枚举[2 * L, 3 * L - 1]这段区间,贡献的值就是sum_number * (2 *…

题目链接:http://codeforces.com/contest/731/problem/F F. Video Cards time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Little Vlad is fond of popular computer game Bota-2. Recently, the developers…

链接: https://codeforces.com/contest/1215/problem/A 题意: The final match of the Berland Football Cup has been held recently. The referee has shown n yellow cards throughout the match. At the beginning of the match there were a1 players in the first team…

Codeforces Round #485 (Div. 2) F. AND Graph 题目连接: http://codeforces.com/contest/987/problem/F Description You are given a set of size $m$ with integer elements between $0$ and $2^{n}-1$ inclusive. Let's build an undirected graph on these integers in…

Codeforces Round #486 (Div. 3) F. Rain and Umbrellas 题目连接: http://codeforces.com/group/T0ITBvoeEx/contest/988/problem/E Description Polycarp lives on a coordinate line at the point x=0. He goes to his friend that lives at the point x=a. Polycarp can…

题目链接 Codeforces Round #501 (Div. 3) F. Bracket Substring 题解 官方题解 http://codeforces.com/blog/entry/60949 ....看不懂 设dp[i][j][l]表示前i位,左括号-右括号=j,匹配到l了 状态转移,枚举下一个要填的括号,用next数组求状态的l,分别转移 代码 #include<bits/stdc++.h> using namespace std; const int maxn = 207;…

Codeforces Round #499 (Div. 1) F. Tree 题目链接 \(\rm CodeForces\):https://codeforces.com/contest/1010/problem/F Solution 设\(v_i\)表示第\(i\)个点的果子数,设\(b_i=v_i-\sum_{x\in son}v_x\),显然依题意要满足\(b_i\geqslant 0\). 根据差分的性质我们可以得到\(\sum b_i=x\). 假设我们硬点树上剩下了\(m\)个点,则…

Codeforces 731 F. Video Cards 题目大意:给一组数,从中选一个数作lead,要求其他所有数减少为其倍数,再求和.问所求和的最大值. 思路:统计每个数字出现的个数,再做前缀和,用于之后快速求和.将原数组排序后去重,枚举每一个数做lead的情况下,其余数减少后再求和的结果.不断维护最大值即可. PS:这里用到了一个方便的函数unique()来去重,使用前需要先将数组排序,参数为数组的首地址和尾后地址,返回新的尾后地址.(该函数没有将重复的元素删除,只是放到了尾地址后面)可…