http://codeforces.com/problemset/problem/899/C tot为奇数时,绝对差为1:tot为偶数时,绝对差为0. 难点在于如何输出. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<cmath> #include<vector> #i…

C. Dividing the numbers Petya has n integers: 1, 2, 3, ..., n. He wants to split these integers in two non-empty groups in such a way that the absolute difference of sums of integers in each group is as small as possible. Help Petya to split the inte…

  Carmichael Numbers  An important topic nowadays in computer science is cryptography. Some people even think that cryptography is the only important field in computer science, and that life would not matter at all without cryptography. Alvaro is one…

UVA 10539 - Almost Prime Numbers 题目链接 题意:给定一个区间,求这个区间中的Almost prime number,Almost prime number的定义为:仅仅能整除一个素数. 思路:既然是仅仅能整除一个素数,那么这些数肯定为素数的x次方(x > 1),那么仅仅要先打出素数表,然后在素数表上暴力找一遍就能够了,由于素数表仅仅要找到sqrt(Max),大概100W,然后每一个数找的复杂度为log(n),这样复杂度是能够接受的. 代码: #include <…

题目链接 Fox Dividing Cheese 思路:求出两个数a和b的最大公约数g,然后求出a/g,b/g,分别记为c和d. 然后考虑c和d,若c或d中存在不为2,3,5的质因子,则直接输出-1(根据题目要求) 计算出c = (2 ^ a2) * (3 ^ a3) * (5 ^ a5)      d = (2 ^ b2) * (3 ^ b3) * (5 ^ b5) 那么答案就是a2 + a3 + a5 + b2 + b3 + b5 #include <bits/stdc++.h> usin…

DZY Loves Fibonacci Numbers Time Limit:4000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Appoint description:  System Crawler  (2014-07-14) Description In mathematical terms, the sequence Fn of Fibonacci numbers is defi…

题目链接:POJ 3641 Description Fermat's theorem states that for any prime number p and for any integer a > 1, ap = a (mod p). That is, if we raise a to the pth power and divide by p, the remainder is a. Some (but not very many) non-prime values of p, know…

题目链接. 题意: 找一个n,和一个m(m < n),求使得1~m的和等于m~n的和,找出10组m,n 分析: 列出来式子就是 m*(m+1)/2 = (n-m+1)*(m+n)/2 化简后为 m*m*2 = n*(n+1) 可以枚举n,然后二分找m,不过这样大约会用10s多,可以打表. 打表程序: #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #…

A. Splitting in Teams time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output There were n groups of students which came to write a training contest. A group is either one person who can write the…

大意: 求将[1,n]划分成两个集合, 且两集合的和的差尽量小. 和/2为偶数最小差一定为0, 和/2为奇数一定为1. 显然可以通过某个前缀和删去一个数得到. #include <iostream> #include <iostream> #include <algorithm> #include <cstdio> #include <math.h> #include <set> #include <map> #inclu…