Everyone knows that DNA strands consist of nucleotides. There are four types of nucleotides: "A", "T", "G", "C". A DNA strand is a sequence of nucleotides. Scientists decided to track evolution of a rare species, wh…
http://codeforces.com/contest/948/problem/A A. Protect Sheep Bob is a farmer. He has a large pasture with many sheep. Recently, he has lost some of them due to wolf attacks. He thus decided to place some shepherd dogs in such a way that all his she…
题: OvO http://codeforces.com/contest/947/problem/D 923D 947D 948E 解: 记要改变的串为 P1 ,记目标串为 P2 由变化规则可得: 1. B -> AC -> AAB -> AAAC -> C ( 即 B -> C -> B ) 2. AB -> AAC -> AAAB -> B (即 AB -> B ) 3. B -> AC -> AB ( 即 B -> AB…
A. Primal Sport 题意:有两个人轮流玩游戏.给出数X(i-1),轮到的人需要找到一个小于X(i-1)的素数x,然后得到Xi,Xi是x的倍数中大于等于X(i-1)的最小的数.现在已知X2,求最小的X0? 思路:根据题意,X1的取值范围为[X1-X2的最大质因子+1,X2),同理可知X0的取值范围为[X1-X1的最大质因子+1,,X1). #include<iostream> #include<cstring> #include<cstdio> #includ…
A. Protect Sheep time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Bob is a farmer. He has a large pasture with many sheep. Recently, he has lost some of them due to wolf attacks. He thus dec…
Alice and Bob begin their day with a quick game. They first choose a starting number X0 ≥ 3 and try to reach one million by the process described below. Alice goes first and then they take alternating turns. In the i-th turn, the player whose turn it…