CF1847E.Triangle Platinum?
普及/提高-
通过率:0%
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题目描述
This is an interactive problem.
Made in Heaven is a rather curious Stand. Of course, it is (arguably) the strongest Stand in existence, but it is also an ardent puzzle enjoyer. For example, it gave Qtaro the following problem recently:
Made in Heaven has n hidden integers a1,a2,…,an ( 3≤n≤5000 , 1≤ai≤4 ). Qtaro must determine all the ai by asking Made in Heaven some queries of the following form:
- In one query Qtaro is allowed to give Made in Heaven three distinct indexes i , j and k ( 1≤i,j,k≤n ).
- If ai,aj,ak form the sides of a non-degenerate triangle † , Made in Heaven will respond with the area of this triangle.
- Otherwise, Made in Heaven will respond with 0 .
By asking at most 5500 such questions, Qtaro must either tell Made in Heaven all the values of the ai , or report that it is not possible to uniquely determine them.
Unfortunately due to the universe reboot, Qtaro is not as smart as Jotaro. Please help Qtaro solve Made In Heaven's problem.
—————————————————————— † Three positive integers a,b,c are said to form the sides of a non-degenerate triangle if and only if all of the following three inequalities hold:
- a+b>c ,
- b+c>a ,
- c+a>b .
输入格式
无
输出格式
The interaction begins with reading n ( 3≤n≤5000 ), the number of hidden integers.
To ask a question corresponding to the triple (i,j,k) ( 1≤i<j<k≤n ), output "? i j k " without quotes. Afterward, you should read a single integer s .
- If s=0 , then ai , aj , and ak are not the sides of a non-degenerate triangle.
- Otherwise, s=16Δ2 , where Δ is the area of the triangle. The area is provided in this format for your convenience so that you need only take integer input.
If the numbers ai cannot be uniquely determined print "! −1 " without quotes. On the other hand, if you have determined all the values of ai print "! a1 a2 … an " on a single line.
The interactor is non-adaptive. The hidden array a1,a2,…,an is fixed beforehand and is not changed during the interaction process.
After printing a query do not forget to output the end of line and flush the output. Otherwise, you will get Idleness limit exceeded. To do this, use:
- fflush(stdout) or cout.flush() in C++;
- System.out.flush() in Java;
- flush(output) in Pascal;
- stdout.flush() in Python;
- see the documentation for other languages.
Hacks
You can hack a solution with the following input format.
The first line contains a single integer n ( 3≤n≤5000 ) — the number of hidden integers.
The second line contains n integers a1,a2,…,an ( 1≤ai≤4 ) — the hidden array.
输入输出样例
输入#1
3 63
输出#1
? 1 2 3 ! -1
输入#2
6 0 0 0 63 15 135
输出#2
? 1 2 3 ? 2 3 4 ? 4 5 6 ? 1 5 6 ? 3 5 6 ? 1 2 4 ! 3 2 1 4 2 2
输入#3
15 3 3 3 3 3 0
输出#3
? 1 2 3 ? 4 6 7 ? 8 9 10 ? 11 12 13 ? 13 14 15 ? 4 5 6 ! -1
输入#4
15 3 15 0 3 3 3
输出#4
? 1 2 3 ? 3 4 5 ? 4 5 6 ? 7 8 9 ? 10 11 12 ? 13 14 15 ! 1 1 1 2 2 4 1 1 1 1 1 1 1 1 1 1
输入#5
10 3 48 3 48 63 0
输出#5
? 1 3 5 ? 4 6 8 ? 1 5 9 ? 6 8 10 ? 4 2 6 ? 7 10 8 ! 1 3 1 2 1 2 4 2 1 2
说明/提示
In the first example, the interaction process happens as follows:
StdinStdoutExplanation3Read n=3 . There are 3 hidden integers? 1 2 3Ask for the area formed by a1 , a2 and a3 63Received 16Δ2=63 . So the area Δ=1663≈1.984313 ! -1Answer that there is no unique array satisfying the queries.From the area received, we can deduce that the numbers that forms the triangle are either ( 4 , 4 , 1 ) or ( 3 , 2 , 2 ) (in some order). As there are multiple arrays of numbers that satisfy the queries, a unique answer cannot be found.
In the second example, the interaction process happens as follows:
StepStdinStdoutExplanation16Read n=6 . There are 6 hidden integers2? 1 2 3Ask for the area formed by a1 , a2 and a3 30Does not form a non-degenerate triangle4? 2 3 4Ask for the area formed by a2 , a3 and a4 50Does not form a non-degenerate triangle6? 4 5 6Ask for the area formed by a4 , a5 and a6 70Does not form a non-degenerate triangle8? 1 5 6Ask for the area formed by a1 , a5 and a6 963Received 16Δ2=63 . So the area Δ=1663≈1.984313 10? 3 5 6Ask for the area formed by a3 , a5 and a6 1115Received 16Δ2=15 . So the area Δ=1615≈0.968245 12? 1 2 4Ask for the area formed by a3 , a5 and a6 13135Received 16Δ2=135 . So the area Δ=16135≈2.904738 14! 3 2 1 4 2 2A unique answer is found, which is a=[3,2,1,4,2,2] .From steps 10 and 11 , we can deduce that the the multiset {a3,a5,a6} must be {2,2,1} .
From steps 8 and 9 , the multiset {a1,a5,a6} must be either {4,4,1} or {3,2,2} .
As {a3,a5,a6} and {a1,a5,a6} share a5 and a6 , we conclude that a5=a6=2 , as well as a1=3 , a3=1 .
From steps 6 and 7 , we know that a5=a6=2 , and a4 , a5 and a6 cannot form a non-degenerate triangle, hence a4=4 .
With all the known information, only a2=2 satisfies the queries made in steps 2 , 3 , 4 , 5 , 12 and 13 .
In the third example, one array that satisfies the queries is [1,1,1,1,3,1,1,1,1,1,1,1,1,1,1] .