#CCC21S5. Math Homework
Math Homework
Your math teacher has given you an assignment involving coming up with a sequence of N integers A,…,A, such that 1≤A≤1000000000 for each i.
The sequence A must also satisfy M requirements, with the i one stating that the GCD (Greatest Common Divisor) of the contiguous subsequence A,…,A (1≤X≤Y ≤N) must be equal to Z. Note that the GCD of a sequence of integers is the largest integer d such that all the numbers in the sequence are divisible by d.
Find any valid sequence A consistent with all of these requirements, or determine that no such sequence exists.
Input Specification
The first line contains two space-separated integers, N and M. The next M lines each contain three space-separated integers, X, Y, and Z (1≤i≤M).
The following table shows how the available 15 marks are distributed.
Subtask | N | M | Zi |
---|---|---|---|
3 marks | 1≤N≤2000 | 1≤M≤2000 | 1≤Zi≤2 for each i |
4 marks | 1≤Zi≤16 for each i | ||
8 marks | 1≤N≤150000 | 1≤M≤150000 |
Output Specification
If no such sequence exists, output the string Impossible
on one line. Otherwise, on one line, output N space-separated integers, forming the sequence A,…,A. If there are multiple possible valid sequences, any valid sequence will be accepted.
Sample Input 1
2 2
1 2 2
2 2 6
Output for Sample Input 1
4 6
Explanation of Output for Sample Input 1
If A=4 and A=6, the GCD of [A,A] is 2 and the GCD of [A] is 6, as required. Please note that other outputs would also be accepted.
Sample Input 2
2 2
1 2 2
2 2 5
Output for Sample Input 2
Impossible
Explanation of Output for Sample Input 2
There exists no sequence [A,A] such that the GCD of [A,A] is 2 and the GCD of [A] is 5.