solution ID 1557946: 3 Mar 2007 time 4.75
solution ID 2456185: 19 Feb 2009 time 1.875

source code is identical.

It seems that TL for this problem has not been changed since the server upgrade this autumn.

I suggest to lower TL from 5s to 2s or rejudge all TLE solutions submitted before server upgrade.

This problem is far from alone in such situation. The best of all would be to update timelimits for all old problems, but it looks impossible.