Codeforces Contest 1055 problem C Lucky Days —— 区间相交最大长度

Bob and Alice are often participating in various programming competitions. Like many competitive programmers, Alice and Bob have good and bad days. They noticed, that their lucky and unlucky days are repeating with some period. For example, for Alice days [la;ra] are lucky, then there are some unlucky days: [ra+1;la+ta−1], and then there are lucky days again: [la+ta;ra+ta] and so on. In other words, the day is lucky for Alice if it lies in the segment [la+kta;ra+kta] for some non-negative integer k.

The Bob’s lucky day have similar structure, however the parameters of his sequence are different: lb, rb, tb. So a day is a lucky for Bob if it lies in a segment [lb+ktb;rb+ktb], for some non-negative integer k.

Alice and Bob want to participate in team competitions together and so they want to find out what is the largest possible number of consecutive days, which are lucky for both Alice and Bob.

Input
The first line contains three integers la, ra, ta (0≤la≤ra≤ta−1,2≤ta≤109) and describes Alice’s lucky days.

The second line contains three integers lb, rb, tb (0≤lb≤rb≤tb−1,2≤tb≤109) and describes Bob’s lucky days.

It is guaranteed that both Alice and Bob have some unlucky days.

Output
Print one integer: the maximum number of days in the row that are lucky for both Alice and Bob.

Examples
inputCopy
0 2 5
1 3 5
outputCopy
2
inputCopy
0 1 3
2 3 6
outputCopy
1
Note
The graphs below correspond to the two sample tests and show the lucky and unlucky days of Alice and Bob as well as the possible solutions for these tests.

题意：

给你一个区间l1,r1，t1是他的循环节长度，再给你l2,r2,t2是它的循环节长度，问你这两个区间相交最大是多少

题解：

这道题很像上次青蛙跳那道题，我们只需要对t1,t2取个gcd，那么所有gcd的倍数就是这两个区间相对位置的改变量。那我们只需要找到l2在l1前面的最后一个位置和在后面的第一个位置，取个最大值就好了

#include
using namespace std;
int main()
{
    int l1,l2,r1,r2,t1,t2;
    scanf("%d%d%d%d%d%d",&l1,&r1,&t1,&l2,&r2,&t2);
    int g=__gcd(t1,t2);
    if(l1