题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1695 题意:x位于区间[a, b],y位于区间[c, d],求满足GCD(x, y) = k的(x, y)有多少组,不考虑顺序. 思路:a = c = 1简化了问题,原问题可以转化为在[1, b/k]和[1, d/k]这两个区间各取一个数,组成的数对是互质的数量,不考虑顺序.我们让d > b,我们枚举区间[1, d/k]的数i作为二元组的第二位,因为不考虑顺序我们考虑第一位的值时,只用考虑小于i的情…

GCD Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4272    Accepted Submission(s): 1492 Problem Description Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y)…

GCD Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 7357    Accepted Submission(s): 2698 Problem Description Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y…

Problem Description Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y) = k. GCD(x, y) means the greatest common divisor of x and y. Since the number of choices may be very large, you're only required to output the t…

GCD Again Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1997    Accepted Submission(s): 772 Problem Description Do you have spent some time to think and try to solve those unsolved problem aft…

GCD Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 3559    Accepted Submission(s): 1921 Problem Description The greatest common divisor GCD(a,b) of two positive integers a and b,sometimes writ…

Description The greatest common divisor GCD(a,b) of two positive integers a and b,sometimes written (a,b),is the largest divisor common to a and b,For example,(1,2)=1,(12,18)=6. (a,b) can be easily found by the Euclidean algorithm. Now Carp is consid…

GCD Again Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2257    Accepted Submission(s): 908 Problem Description Do you have spent some time to think and try to solve those unsolved problem aft…

题目链接 题意 : 从[a,b]中找一个x,[c,d]中找一个y,要求GCD(x,y)= k.求满足这样条件的(x,y)的对数.(3,5)和(5,3)视为一组样例 . 思路 :要求满足GCD(x,y)=k的对数,则将b/k,d/k,然后求GCD(x,y)=1的对数即可.假设b/k >= d/k ;对于1到b/k中的某个数s,如果s<=d/k,则因为会有(x,y)和(y,x)这种会重复的情况,所以这时候的对数就是比s小的与s互质的数的个数,即s的欧拉函数.至于重复的情况是指:在d/k中可能有大于…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1695 题目解析: Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y) = k. 题目又说a==c==1,所以就是求[1,b]与[1,d]中gcd等于k的个数,因为若gcd(x,y)==z,那么gcd(x/z,y/z)==1,又因为不是z的倍数的肯定不是,所以不是z的倍数的可以直接去…