题目大意: 给出一个$d$维矩形,第i维的范围是$[0, l_i]$. 求满足$x_1 + x_2 + ...x_d \leq s$ 的点构成的单纯形体积. $d, l_i \leq 300$ 题解: watashi学长的blog传送门. 给出了求$a_1x_1 + a_2x_2 + ...a_dx_d \leq b $的通用做法.答案就是一个神奇的式子$\frac{1}{n!} * \sum_{I \subseteq S}{(-1)^{|I|}}*max\{0, b - \sum_{i \in…

题目:Problem A. Arithmetic DerivativeInput file: standard inputOutput file: standard inputTime limit: 1 secondMemory limit: 256 mebibytesLets define an arithmetic derivative:• if p = 1 then p0 = 0;• if p is prime then p0 = 1;• if p is not prime then n0…

题意:给你一张简单无向图(但可能不连通),再给你一个K,让你求解任意一个问题:K染色或者输出一条K长路径. 直接贪心染色,对一个点染上其相邻的点的颜色集合之中,未出现过的最小的颜色. 如果染成就染成了.如果到某个点,发现染不成,则倒着按照颜色从大到小回去,则一定恰好可以找出一条K长度的路径. #include<cstdio> #include<cstring> using namespace std; int first[1005],next[20005],v[20005],e,c…

题意:有n个土豆,每个有体积V(i),你可以将每个土豆等分为不超过K份,问你最大块和最小块比值最小为多少. 直接枚举切法,只有n*K种,然后保证其为最大块,去算其他块的切法,即让其他块切得尽可能大即可.O(n*n*K). #include<cstdio> #include<cstring> using namespace std; int n,K,a[105],ans1=150,ans2=1,x[105],ansx[105]; int main(){ // freopen(&quo…

给你n个字符串,问你最小的长度的前缀,使得每个字符串任意循环滑动之后,这些前缀都两两不同. 二分答案mid之后,将每个字符串长度为mid的循环子串都哈希出来,相当于对每个字符串,找一个与其他字符串所选定的子串不同的子串,是个二分图最大匹配的模型,可以匈牙利或者Dinic跑最大流看是否满流. 一个小优化是对于某个字符串,如果其所有不同的子串数量超过n,那么一定满足,可以直接删去. 卡常数,不能用set,map啥的,采取了用数组记录哈希值,排序后二分的手段进行去重和离散化. #include<cst…

思路: 直接二分长度不可行,因为有负数. 考虑枚举坐便删l个数,那如果可以在短时间内求出符合条件的右边最小删的数的个数,这题便可做了. 即:当左边删l个数时,要使sum[n]-sum[l]-fsum[n+1-x] <= s成立,求出最小的x.(sum为前缀和,fsum为后缀和) 思考后可以发现可行的fsum[x]必然要是正数,可能的答案x必然是单调递增的(x从0开始). 所以维护一个大于0的递增的单调栈即可,在里面二分找答案. #include <bits/stdc++.h> using…

题目: Problem F. Matrix GameInput file: standard inputOutput file: standard inputTime limit: 1 secondMemory limit: 256 mebibytesAlice and Bob are playing the next game. Both have same matrix N × M filled with digits from 0 to 9.Alice cuts the matrix ve…

题目:Problem J. TerminalInput file: standard inputOutput file: standard inputTime limit: 2 secondsMemory limit: 256 mebibytesN programmers from M teams are waiting at the terminal of airport. There are two shuttles at the exitof terminal, each shuttle…

题目:Problem L. Canonical duelInput file: standard inputOutput file: standard outputTime limit: 2 secondsMemory limit: 256 megabytesIn the game «Canonical duel» board N × M is used. Some of the cells of the board contain turrets. Aturret is the unit wi…

题目:Problem D. Clones and TreasuresInput file: standard inputOutput file: standard outputTime limit: 1 secondMemory limit: 256 mebibytesThe magical treasury consists of n sequential rooms. Due to construction of treasury its impossible togo from room…