Divide or die
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Read problems statements in Mandarin Chinese and Russian.
Many of you know about a popular logic game called Euclid: The Game. Everything was fine, but then the game came into the real world because of a horrible mistake of one of the players. Now the whole world is in danger! The world can be described as the Cartesian plane where each point has two real coordinates x and y. In order to save the world you are to complete the following task.
Suppose you are given an angle which measures exactly N degrees, where N is an integer with 0 < N < 360.
You are to answer the question: is it possible to construct, using only a straightedge and compass, N-1 rays which divide this angle into N equal angles of size 1 degree?
If the answer is YES, you must demonstrate this by listing the steps you would take to generate these rays.
You will be given three points: V, R1, and R2. The angle you are to consider is the clockwise angle from the ray VR1 to the ray VR2. This angle, in degrees, will always be an integer N with 0 < N < 360.
If the above construction is possible, you are able to perform two types of operations:
- Construct a line that connects two known points A and B.
- Construct a circle with center at a known point C, and radius equal to the distance between two known points A and B.
A point P is called known if it satisfies one of these two statements:
- P is equal to one of V, R1, or R2.
- P is one of the points of intersection of any lines or circles constructed in previous steps.
The construction is complete once you have found N-1 known points: D1, D2, ..., DN-1, such that the rays VD1, VD2, ..., VDN-1, divide the given angle into N equal angles of size 1 degree.
The first line of the input files contains two space-separated real numbers with precision at least 1e-6: the x and y coordinates of V. The second and third lines contain the coordinates of R1 and R2 similarly.
The first line of the output should contain a single word: YES or NO - whether it is theoretically possible to perform the construction described above with a straightedge and compass only.
If your answer is NO, do not output anything else.
If your answer is YES, the following lines should describe your operations, one per line, as follows.
If you want to construct a line between known points A and B, output the word Line followed by 4 space-separated numbers - the coordinates of A, followed by the coordinates of B. A and B must not be the same point.
If you want to construct a circle with center at the known point C, and radius equal to the distance between known points A and B, output the word Circle followed by 6 space-separated numbers - the coordinates of C, followed by the coordinates of A and B. A and B must not be the same point, but there are no such restrictions on C.
Once you have performed all necessary operations, output a single line with the word Answer. In each of the next N-1 lines, output two space-separated numbers - the coordinates of D1, D2, ..., DN-1, listed in clockwise order. Each of these must be known points.
The absolute value of any coordinate given in the input does not exceed 1000.
All input coordinates have a precision of at least 1e-6. Prior to precision adjustments, the clockwise angle formed by the input points, in degrees, is guaranteed to be an integer N with 0 < N < 360.
All coordinates in the output are compared for equality with precision 1e-5. This means that you can use point H as a known point if there is a true known point K with |Hx-Kx| and |Hy-Ky| no more than 1e-5 each.
Your solution must not output more than 1000 operations.
Subtask #1 [25 points]: N ≤ 4
Subtask #2 [75 points]: maximum constraints
Input: -679.6073275406 -315.6362656580 -844.0655568007 -298.0169842162 -841.1364219780 -292.6039079355 Output: YES Line -679.6073275406 -315.6362656580 -844.0655568007 -298.0169842162 Line -679.6073275406 -315.6362656580 -841.1364219780 -292.6039079355 Circle -679.6073275406 -315.6362656580 -679.6073275406 -315.6362656580 -844.0655 568007 -298.0169842162 Line -679.6073275406 -315.6362656580 -841.1364219780 -292.6039079355 Line -844.0655568007 -298.0169842162 -843.3504692364 -292.2882079766 Circle -844.0655568007 -298.0169842162 -844.0655568007 -298.0169842162 -843.3504 692364 -292.2882079766 Circle -843.3504692364 -292.2882079766 -844.0655568007 -298.0169842162 -843.3504 692364 -292.2882079766 Line -848.6692787746 -294.5333120998 -838.7467472625 -295.7718800931 Answer -843.7080130185 -295.1525960964
There are other acceptable solutions.
The line breaks inside the second to last coordinates for each circle are for website display reasons only, and should not exist in your output.
The measure of the given angle is 2 degrees. It is well known that we can bisect any angle with a compass and straightedge, so we can certainly do so for a 2 degree angle. This divides the angle into two 1-degree angles as required. The method presented is one way of doing so and looks like this:
|Tags||angles, binary-search, dec14, geometry, medium, pavel1996|
|Time Limit:||1 sec|
|Source Limit:||50000 Bytes|
|Languages:||C, CPP14, JAVA, PYTH, PYTH 3.6, CS2, PAS fpc, PAS gpc, RUBY, PHP, GO, NODEJS, HASK, SCALA, D, PERL, FORT, WSPC, ADA, CAML, ICK, BF, ASM, CLPS, PRLG, ICON, SCM qobi, PIKE, ST, NICE, LUA, BASH, NEM, LISP sbcl, LISP clisp, SCM guile, JS, ERL, TCL, PERL6, TEXT, CLOJ, FS|
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