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???Finding the Radius for an Inserted Circle

热度:25   发布时间:2023-11-03 00:56:37.0

Three circles C_{a}C?a??C_{b}C?b??, and C_{c}C?c??, all with radius RR and tangent to each other, are located in two-dimensional space as shown in Figure 11. A smaller circle C_{1}C?1?? with radius R_{1}R?1?? (R_{1}<RR?1??<R) is then inserted into the blank area bounded by C_{a}C?a??C_{b}C?b??, and C_{c}C?c?? so that C_{1}C?1?? is tangent to the three outer circles, C_{a}C?a??C_{b}C?b??, and C_{c}C?c??. Now, we keep inserting a number of smaller and smaller circles C_{k}\ (2 \leq k \leq N)C?k?? (2kN) with the corresponding radius R_{k}R?k?? into the blank area bounded by C_{a}C?a??C_{c}C?c?? and C_{k-1}C?k?1?? (2 \leq k \leq N)(2kN), so that every time when the insertion occurs, the inserted circle C_{k}C?k?? is always tangent to the three outer circles C_{a}C?a??C_{c}C?c?? and C_{k-1}C?k?1??, as shown in Figure 11

Figure 1.

(Left) Inserting a smaller circle C_{1}C?1?? into a blank area bounded by the circle C_{a}C?a??C_{b}C?b?? and C_{c}C?c??.

(Right) An enlarged view of inserting a smaller and smaller circle C_{k}C?k?? into a blank area bounded by C_{a}C?a??C_{c}C?c?? and C_{k-1}C?k?1?? (2 \leq k \leq N2kN), so that the inserted circle C_{k}C?k?? is always tangent to the three outer circles, C_{a}C?a??C_{c}C?c??, and C_{k-1}C?k?1??.

Now, given the parameters RR and kk, please write a program to calculate the value of R_{k}R?k??, i.e., the radius of the k-thk?th inserted circle. Please note that since the value of R_kR?k?? may not be an integer, you only need to report the integer part of R_{k}R?k??. For example, if you find that R_{k}R?k?? = 1259.89981259.8998 for some kk, then the answer you should report is 12591259.

Another example, if R_{k}R?k?? = 39.102939.1029 for some kk, then the answer you should report is 3939.

Assume that the total number of the inserted circles is no more than 1010, i.e., N \leq 10N10. Furthermore, you may assume \pi = 3.14159π=3.14159. The range of each parameter is as below:

1 \leq k \leq N1kN, and 10^{4} \leq R \leq 10^{7}10?4??R10?7??.

Input Format

Contains l + 3l+3 lines.

Line 11ll ----------------- the number of test cases, ll is an integer.

Line 22RR ---------------- RR is a an integer followed by a decimal point,then followed by a digit.

Line 33kk ---------------- test case #11kk is an integer.

\ldots

Line i+2i+2kk ----------------- test case # ii.

\ldots

Line l +2l+2kk ------------ test case #ll.

Line l + 3l+3-1?1 ---------- a constant -1?1 representing the end of the input file.

Output Format

Contains ll lines.

Line 11kk R_{k}R?k?? ----------------output for the value of kk and R_{k}R?k?? at the test case #11, each of which should be separated by a blank.

\ldots

Line iikk R_{k}R?k?? ----------------output for kk and the value of R_{k}R?k?? at the test case # ii, each of which should be separated by a blank.

Line llkk R_{k}R?k?? ----------------output for kk and the value ofR_{k}R?k?? at the test case # ll, each of which should be separated by a blank.

样例输入

1
152973.6
1
-1

样例输出

1 23665

题目来源

2017 ACM-ICPC 亚洲区(南宁赛区)网络赛

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