That doesn't help - time is counted from midnight, so if you solve the problem on one account and then another, the second account will have a strictly worse time. About all it can really do is mess with the score distribution.
Also, the input data for each problem is randomized per user, so you really do need a proper programmatic solution (i.e. simply copying another person's answer is unlikely to work).
You could hurt other people's scores though right? Like if you and one other competitor traded wins on different days, but you had a second account that you posted the same solution to, your competitor would get third place on your winning days (and thus fewer points).
Also, the input data for each problem is randomized per user, so you really do need a proper programmatic solution (i.e. simply copying another person's answer is unlikely to work).