2026 年 USACO竞赛 首场比赛银奖组问题二—Mooclear Reactor

Bessie is designing a nuclear reactor to power Farmer John's lucrative new AI data center business, CowWeave!

The reactor core consists of N (1≤N≤2⋅105 ) fuel rods, numbered 1 through N. The i-th rod has a "stable operating range" [li,ri] (−109liri≤109), meaning it can only generate power if its energy ai (chosen by Bessie) satisfies liairi; otherwise, it sits idle and does not generate power. Moreover, ai must always be  an integer. Note that aican be any integer, not limited to [−109,109].

However, quantum interactions between the rods mean that there are M constraints of the form (x,y,z) where Bessie must satisfy ax+ay=z (1≤x,yN and −109≤z≤109) to prevent the reactor from melting down.

Help Bessie find the maximum number of power-generating rods she can achieve in her design without it melting down!

INPUT FORMAT (input arrives from the terminal / stdin):

The first line contains T(1≤T≤10), the number of independent tests. Each test is specified in the following format:

The first line contains the two integers N and M.
The second line contains the N integers l1,…,lN.
The third line contains the N integers  r1,…,rN.
The next M lines each contain three integers x, y, and z, each representing a constraint.

It is guaranteed that neither the sum of N nor the sum of M over all tests exceeds 4⋅ 105 .

OUTPUT FORMAT (print output to the terminal / stdout):

If no choice of rod energies exists that satisfies all constraints, output −1. Otherwise, output the maximum number of power-generating rods Bessie can achieve.

SAMPLE INPUT:

2
3 3
1 2 3
1 2 3
1 1 2
2 2 10
1 1 4
3 2
1 2 3
1 2 3
1 1 2
2 2 10

SAMPLE OUTPUT:

-1
2

In the second test, the constraints require that:

1.a1+a1=2
2.a2+a2=10

Choosing energies a=[1,5,3] results in 2 power-generating rods because:

l1=1≤a1≤1=r1
l3=3≤a3≤3=r3

and a satisfies all required constraints.

SAMPLE INPUT:

1
3 2
10 -10 10
10 -10 10
1 2 0
2 3 0

SAMPLE OUTPUT:

3

Choosing rod energies a=[10,−10,10] results in 3 power-generating rods.

SAMPLE INPUT:

5
3 3
1 -1 0
2 1 2
1 2 1
1 3 4
2 3 3
1 1
-100
100
1 1 3
1 1
-100
100
1 1 2
1 2
-100
100
1 1 2
1 1 4
1 2
-100
100
1 1 2
1 1 2

SAMPLE OUTPUT:

2
-1
1
-1
1

SCORING:

Input 4: x=y for all constraints.
Inputs 5-7: |xy|=1 for all constraints.
Inputs 8-10: |xy|≤1 for all constraints.
Inputs 11-13: No additional conditions.

Problem credits: Akshaj Arora