atcoder#SUMITB2019F. Interval Running
Interval Running
Score: points
Problem Statement
Takahashi and Aoki are training for long-distance races in an infinitely long straight course running from west to east.
They start simultaneously at the same point and moves as follows towards the east:
- Takahashi runs meters per minute for the first minutes, then runs at meters per minute for the subsequent minutes, and alternates between these two modes forever.
- Aoki runs meters per minute for the first minutes, then runs at meters per minute for the subsequent minutes, and alternates between these two modes forever.
How many times will Takahashi and Aoki meet each other, that is, come to the same point? We do not count the start of the run. If they meet infinitely many times, report that fact.
Constraints
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
Output
Print the number of times Takahashi and Aoki will meet each other.
If they meet infinitely many times, print infinity
instead.
1 2
10 10
12 4
1
They will meet just once, minutes after they start, at meters from where they start.
100 1
101 101
102 1
infinity
They will meet minutes after they start, that is, they will meet infinitely many times.
12000 15700
3390000000 3810000000
5550000000 2130000000
113
The values in input may not fit into a -bit integer type.