A. Buses Between Cities 题目连接: http://www.codeforces.com/contest/665/problem/A Description Buses run between the cities A and B, the first one is at 05:00 AM and the last one departs not later than at 11:59 PM. A bus from the city A departs every a mi…

题意: 从A到B的汽车每隔 a 分钟发车一次,从A到B要ta分钟. 从B到A汽车每隔b分钟发车一次,从B到A要ta分钟. Simion从A出发,问他在A->B的途中共遇到了多少辆车. 汽车都是从上午5.00出发,最晚到晚上11.59. 思路: 这种CF题模拟模拟!!!讲道理模拟题的能力好弱啊!!! 直接就是从5:00到11:59模拟一发,然后中间只会有两种可能,一个是那个人还没出去之前,一个是那个人出去了以后,车子在路上. 然后就是纯模拟就可以了,但是模拟的条件,还是靠感觉写的好啊 #inclu…

F. Four Divisors 题目连接: http://www.codeforces.com/contest/665/problem/F Description If an integer a is divisible by another integer b, then b is called the divisor of a. For example: 12 has positive 6 divisors. They are 1, 2, 3, 4, 6 and 12. Let's def…

链接:http://codeforces.com/contest/665/problem/E 题意:求规模为1e6数组中,连续子串xor值大于等于k值的子串数: 思路:xor为和模2的性质,所以先预处理之后,可以枚举这种确实子串区间的方法为O(n^2): 优化?把每一个前缀xor扔到二叉树中,从根节点出发,以高位前缀值的二进制数构造一颗二叉树,这样就可以在构造的时候,实现对子树节点个数的求解:之后在线求解到当前节点的可选的前缀xor的个数, 即以k为主线 如果当前位k为1,则在前缀二叉树中只能找…

E. Beautiful Subarrays 题目连接: http://www.codeforces.com/contest/665/problem/E Description One day, ZS the Coder wrote down an array of integers a with elements a1,  a2,  ...,  an. A subarray of the array a is a sequence al,  al  +  1,  ...,  ar for so…

D. Simple Subset 题目连接: http://www.codeforces.com/contest/665/problem/D Description A tuple of positive integers {x1, x2, ..., xk} is called simple if for all pairs of positive integers (i,  j) (1  ≤ i  <  j ≤ k), xi  +  xj is a prime. You are given a…

C. Simple Strings 题目连接: http://www.codeforces.com/contest/665/problem/C Description zscoder loves simple strings! A string t is called simple if every pair of adjacent characters are distinct. For example ab, aba, zscoder are simple whereas aa, add a…

B. Shopping 题目连接: http://www.codeforces.com/contest/665/problem/B Description Ayush is a cashier at the shopping center. Recently his department has started a ''click and collect" service which allows users to shop online. The store contains k items.…

先转换成异或前缀和,变成询问两个数异或≥k的方案数. 分治然后Trie树即可. #include<cstdio> #include<algorithm> #define N 1000010 #define mid (l+r>>1) #define ll long long using namespace std; int n,k,a[N];ll ans; struct Trie { ][],tot,sum[N*]; void init() { ;i<=tot;i+…

发生了好多事情 再加上昨晚教育场的爆零 ..真的烦 题目链接 A题经典题 这个题我一开始推公式wa 其实一看到数据范围 就算遍历也OK 存在的问题进制错误 .. 思路不清晰 两个线段有交叉 并不是端点落在另一个线段 包含的情况落在线段外 a车不影响 结果直接给忽略 #include <iostream> #include<cstdio> using namespace std; int main() { int a,ta,b,tb,hh,mm; cin>>a>&g…