题目链接 这个题取模的时候挺坑的!!! 题意:div(x , b) / mod(x , b) = k( 1 <= k <= a).求x的和 分析: 我们知道mod(x % b)的取值范围为 1  - (b-1).那么我们可以从这一点入口来进行解题.. mod (x, b) = 1 时, x  =  b + 1, 2b + 1, 3b + 1..... a * b + 1. mod (x , b) = 2 时, x =  2b + 2, 4b + 2, 6b + 2, ..... 2a * b…

C. Dreamoon and Sums   Dreamoon loves summing up something for no reason. One day he obtains two integers a and b occasionally. He wants to calculate the sum of all nice integers. Positive integer x is called nice if  and , where k is some integer nu…

C. Dreamoon and Sums time limit per test 1.5 seconds memory limit per test 256 megabytes input standard input output standard output Dreamoon loves summing up something for no reason. One day he obtains two integers a and b occasionally. He wants to…

http://codeforces.com/contest/476/problem/C C. Dreamoon and Sums time limit per test 1.5 seconds memory limit per test 256 megabytes input standard input output standard output Dreamoon loves summing up something for no reason. One day he obtains two…

题目链接 Dreamoon loves summing up something for no reason. One day he obtains two integers a and b occasionally. He wants to calculate the sum of all nice integers. Positive integer x is called nice if  and , where k is some integer number in range[1, a…

题目链接 题意: 1-m中,四个数凑成一组,满足任意2个数的gcd=k,求一个最小的m使得凑成n组解.并输出 分析: 直接粘一下两个很有意思的分析.. 分析1: 那我们就弄成每组数字都互质,然后全体乘以k不就行了么…… 然后看了看样例…… 这个该怎么说……我是觉得额这道题的output暴露了数据规律怎么破……我算是看出规律再证明的方式A的这道题 当时我看到22那个样例的时候……在想他干嘛要把22放这里……然后发现 2/4/6/10 14/16/18/22也是行的哇…… 化成乘以k之前的数据………

E. Dreamoon and Strings 题目连接: http://www.codeforces.com/contest/476/problem/E Description Dreamoon has a string s and a pattern string p. He first removes exactly x characters from s obtaining string s' as a result. Then he calculates that is defined…

D. Dreamoon and Sets 题目连接: http://www.codeforces.com/contest/476/problem/D Description Dreamoon likes to play with sets, integers and . is defined as the largest positive integer that divides both a and b. Let S be a set of exactly four distinct inte…

B. Dreamoon and WiFi 题目连接: http://www.codeforces.com/contest/476/problem/B Description Dreamoon is standing at the position 0 on a number line. Drazil is sending a list of commands through Wi-Fi to Dreamoon's smartphone and Dreamoon follows them. Eac…

A. Dreamoon and Stairs 题目连接: http://www.codeforces.com/contest/476/problem/A Description Dreamoon wants to climb up a stair of n steps. He can climb 1 or 2 steps at each move. Dreamoon wants the number of moves to be a multiple of an integer m. What…