[BOJ 15299] Best Rational Approximation
View as PDFMany microcontrollers have no floating point unit but do have a (reasonably) fast integer divide unit. In these cases it may pay to use rational values to approximate floating point constants. For instance,</p>
355/113 = 3.1415929203539823008849557522124
is a quite good approximation to
π = 3.14159265358979323846
A best rational approximation, p/q, to a real number, x, with denominator at most M is a rational number, p/q (in lowest terms), with q <= M such that, for any integers, a and b with b <= M, and a and b relatively prime, p/q is at least as close to x as a/b:
|x – p/q| ≤ |x – a/b|
Write a program to compute the best rational approximation to a real number, x, with denominator at most M.
입력 형식
The first line of input contains a single integer P, (1 ≤ P ≤ 1000), which is the number of data sets that follow. Each data set should be processed identically and independently.</p>
Each data set consists of a single line of input. It contains the data set number, K, followed by the maximum denominator value, M (15 ≤ M ≤ 100000), followed by a floating-point value, x, (0 ≤ x < 1).
출력 형식
For each data set there is a single line of output. The single output line consists of the data set number, K, followed by a single space followed by the numerator, p, of the best rational approximation to x, followed by a forward slash (/) followed by the denominator, q, of the best rational approximation to x.
예제 입력
3
1 100000 .141592653589793238
2 255 .141592653589793238
3 15 .141592653589793238
예제 출력
1 14093/99532
2 16/113
3 1/7
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