8. Greatest Common Divisors
Description
A common divisor for two positive numbers is a number which both numbers are divisible by. It’s easy to calculate the greatest common divisor between tow numbers. But your teacher wants to give you a harder task, in this task you have to find the greatest common divisor d between two integers a and b that is in a given range from low to high (inclusive), i.e. low<=d<=high. It is possible that there is no common divisor in the given range.
Input
The first line contains an integer T (1<=T<=10)- indicating the number of test cases.
For each case, there are four integers a, b, low, high (1<=a,b<=1000,1<=low<=high<=1000) in one line.
Output
For each case, print the greatest common divisor between a and b in given range, if there is no common divisor in given range, you should print “No answer”(without quotes).
Sample Input
3
9 27 1 5
9 27 10 11
9 27 9 11
Sample Output
3
No answer
9
思路
直接遍历那个区间中的数字,判断是否既能除以A又能除以B。
代码
#include<iostream>
using namespace std;
int main()
{
int times;
cin >> times;
while(times--)
{
int a, b, low, high;
cin >> a >> b >> low >> high;
bool result;
int divisor;
for(divisor = high; divisor >= low; divisor--)
{
if(a % divisor == 0 && b % divisor == 0) {
result = true;
break;
}
result = false;
}
if(result) cout << divisor << endl;
else cout << "No answer" << endl;
}
return 0;
}