Problem G Good Teacher I want to be a good teacher, so at least I need to remember all the student names. However, there are too many students, so I failed. It is a shame, so I don't want my students to know this. Whenever I need to call someone, I c…

Problem A Almost Palindrome Given a line of text, find the longest almost-palindrome substring. A string S is almost-palindrome if S begins and ends with a letter, and a(S) and b(S) have at most 2k positions with different characters Here a(S) is the…

Problem F Funny Car Racing There is a funny car racing in a city with n junctions and m directed roads. The funny part is: each road is open and closed periodically. Each road is associate with two integers (a, b), that means the road will be open fo…

Problem H High bridge, low bridge Q: There are one high bridge and one low bridge across the river. The river has flooded twice, why the high bridge is flooded twice but the low bridge is flooded only once? A: Because the lower bridge is so low that…

Problem I Interesting Calculator There is an interesting calculator. It has 3 rows of button. Row 1: button 0, 1, 2, 3, ..., 9. Pressing each button appends that digit to the end of the display. Row 2: button +0, +1, +2, +3, ..., +9. Pressing each bu…

Problem J Joking with Fermat's Last Theorem Fermat's Last Theorem: no three positive integers a, b, and c can satisfy the equation an + bn = cn for any integer value of n greater than two. From the theorem, we know that a3 + b3 = c3 has no positive i…

Problem L Last Blood In many programming contests, special prizes are given to teams who solved a particular problem first. We call the first accepted solution "First Blood". It's an interesting idea to set prizes for "Last Blood". The…

Problem C Character Recognition? Write a program that recognizes characters. Don't worry, because you only need to recognize three digits: 1, 2 and 3. Here they are: .*. *** *** .*. ..* ..* .*. *** *** .*. *.. ..* .*. *** *** Input The input contains…

题目链接:https://codeforces.com/gym/101991/problem/G 题意:给出 n 个数,q 次询问区间[ li,ri ]之间有多少个 GCD = di 的连续子区间. 题解:类似HDU 5726,可以先看一下这个blog:https://blog.csdn.net/u013569304/article/details/51987053 考虑离线,先预处理出[ 1,n ]之间所有的GCD,同时需要记录每种 GCD 的区间,方法是固定一个右端点R,对于区间[ L,R…

数值计算: 这种积分的计算方法很好,学习一下! 代码: #include <iostream> #include <cmath> using namespace std; ; double func(double a, double b, double x) { double r = a * exp(- x*x) + b * sqrt(x); return r*r; } double integrate(double a, double b, double h) { unsigne…