Brief Intro: 对于四元组(v,c,l,r),求其子序列中v最大的和,并使其满足: 1.Ci+Li+Ri相同 2.L1=0,Rn=0 3.Li=Sigma(C1...Ci-1) Solution: 算是有条件约束的DP吧 设dp[k]为选到k且选k的最大值 对于每个条件,我们这样处理: 1.将所有数据按Ci+Li+Ri的和进行分组处理 2.当Li=0时,将其视为起点:当Ri=0时,用dp[i]去更新res 3.此条件可转换为:仅当Lp=Lq+Cq时,dp[p]可由dp[q]转移而来 于…

D. Don't fear, DravDe is kind time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A motorcade of n trucks, driving from city «Z» to city «З», has approached a tunnel, known as Tunnel of Horror…

主题链接:点击打开链接 为了让球队后,删除是合法的.也就是说,对于每一个车辆, l+r+c 一样,按l+r+c分类. 然后dp一下. #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <math.h> #include <set> #include <vector> #include <map&…

题目传送门:http://codeforces.com/problemset/problem/28/D 题意:给你$N$个物品,每个物品有其价格$P_i$,之前必须要买的物品价格和$L_i$,之后必须要买的物品价格和$R_i$和价值$W_i$.试给出一种物品的选择方案,使得满足所有选择的物品的条件且选择物品的价值和最大(物品的选择顺序必须要与原来的顺序相同).$N \leq 10^5 , P , L , R \leq 10^5 , W \leq 10^4$ 像背包DP,所以就是背包DP(雾 我们…

传送门 Description 一个有N辆卡车的车队从城市Z驶向城市3,来到了一条叫做"恐惧隧道"的隧道.在卡车司机中,有传言说怪物DravDe在那条隧道里搜寻司机.有些司机害怕先走,而其他人则害怕后走.但让我们考虑一般情况,每辆卡车用四个数字描述: •v,卡车的价值,包括乘客和货物 •c,乘客数量,包括司机本人 •l,当前辆卡车之前应该进入的隧道的总人数,这样,当前司机就可以克服他的恐惧(如果怪物出现在那辆车前面,它会先吃掉他们) •r,当前辆卡车之后应该进入的隧道的总人数,这样,当…

传送门 题意:\(n\)个位置,每个位置有价值\(v_i\)和重量\(p_i\),要选出一些位置,如果要选位置\(i\),那么前面选的重量之和要为\(l_i\),后面选的重量之和要为\(r_i\),求一个方案使得价值和最大 这个限制很舒服,可以设\(f_i\)为从前面开始选,选第\(i\)个的最大价值,转移枚举前面的\(j\),如果能从\(j\)转移过来,根据条件,要求\(l_i=l_j+p_i\&\&r_i=r_j-p_i\),记个转移前缀就可以输出方案了 但是这样还不优,我们可以发现对…

补一篇以前的扩展欧几里得的题,发现以前写错了竟然也过了,可能数据水??? 这个题还是很有意思的,和队友吵了两天,一边吵一边发现问题??? L. Knights without Fear and Reproach http://codeforces.com/gym/100812/problem/L time limit per test 2.0 s memory limit per test 256 MB input standard input output standard output Th…

Last summer Peter was at his granny's in the country, when a wolf attacked sheep in the nearby forest. Now he fears to walk through the forest, to walk round the forest, even to get out of the house. He explains this not by the fear of the wolf, but…

G - Animals Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 35D Description input input.txt output output.txt Once upon a time DravDe, an outstanding person famous for his professional ac…

Codeforces 15E Triangles Last summer Peter was at his granny's in the country, when a wolf attacked sheep in the nearby forest. Now he fears to walk through the forest, to walk round the forest, even to get out of the house. He explains this not by t…