Rocket Stages: Input
Rocket Stages: Input
Rocket Stages: Input
Many rockets are made up of several stages to increase efficiency. When the fuel in one stage burns up,
the stage can be discarded, reducing the weight of the remaining rocket. The first stage needs a strong
engine capable of lifting the whole rocket, while later stages can have smaller engines.
In this problem, you will determine which stages to put together to maximize the upward velocity
of the rocket when all the fuel has burned.
For each stage, you will be given:
Assume that the rocket points straight upward for the duration of the flight. Two forces act on
the rocket: the force of the engine, which is T newtons upwards, and the force of gravity, which is
9.8 M newtons downwards, where M is the total mass of the rocket in kilograms, including fuel. The
acceleration of the rocket is F divided by M metres per second per second upwards, where F is the
total net force acting on the rocket in newtons, and M is the total mass of the rocket in kilograms,
including fuel. As soon as a stage finishes burning, it is immediately discarded and the next stage starts
to burn. The final velocity of the rocket is the integral of the net acceleration (due to gravity and the
engine) over time.
Due to safety regulations, the net acceleration of the rocket is never allowed to be downwards, until
the rocket runs out of fuel.
Also due to safety regulations, the total mass of the rocket cannot exceed 10000 kilograms.
The rocket must have at least one stage.
Input
The first line of input contains one integer specifying the number of test cases to follow. Each test case
begins with a line containing an integer N , the number of rocket stages in the current test case. There
will be no more than 1000 stages. This line is followed by N lines, one for each stage. Each of these
lines contains the four integers S, L, T , C that describe a stage, as explained above. Each of these
integers can be represented by a 32-bit unsigned binary number. The order of the stages as listed must
be preserved but some stages (including, possibly, the first stage) may be left out of the rocket. The
stage listed first is at the top of the rocket (and will burn last).
For every test case in the input, it is always possible to construct at least one rocket satisfying all
the requirements of the problem statement.
Output
For each test case, output a line containing a single integer, the maximum possible speed in metres per
second of the rocket when it has finished burning, rounded to the nearest metre per second.
Universidad de Valladolid OJ: 11502 – Rocket Stages 2/2
Sample Input
1
1
9999 1 1000000 1
Sample Output
90