結果

問題 No.724 円と円の間の円
ユーザー uwiuwi
提出日時 2018-08-03 22:57:24
言語 Java
(openjdk 23)
結果
AC  
実行時間 125 ms / 2,000 ms
コード長 4,117 bytes
コンパイル時間 3,963 ms
コンパイル使用メモリ 87,156 KB
実行使用メモリ 54,136 KB
最終ジャッジ日時 2024-09-19 17:36:45
合計ジャッジ時間 7,947 ms
ジャッジサーバーID
(参考情報)
judge2 / judge5
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 24
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ソースコード

diff #
プレゼンテーションモードにする

package contest180803;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
public class D {
InputStream is;
PrintWriter out;
String INPUT = "";
// (x, y)
// (x-a)^2+y^2=(a+y)^2
// (x-b)^2+y^2=(b-y)^2
public static double[] circumcircle(double[] a, double[] b, double[] c)
{
double ax = a[0], ay = a[1];
double bx = b[0], by = b[1];
double cx = c[0], cy = c[1];
if((bx-ax)*(cy-ay)-(by-ay)*(cx-ax) == 0)return null; // 0
double D = 2*(ax*(by-cy)+bx*(cy-ay)+cx*(ay-by));
double X = ((ax*ax+ay*ay)*(by-cy)+(bx*bx+by*by)*(cy-ay)+(cx*cx+cy*cy)*(ay-by))/D;
double Y = ((ax*ax+ay*ay)*(cx-bx)+(bx*bx+by*by)*(ax-cx)+(cx*cx+cy*cy)*(bx-ax))/D;
double R = Math.sqrt((X-ax)*(X-ax)+(Y-ay)*(Y-ay));
return new double[]{X, Y, R};
}
double[] inv(double[] a)
{
double d = Math.sqrt(a[0]*a[0]+a[1]*a[1]);
a[0] = -a[0]/d/d;
a[1] = -a[1]/d/d;
return a;
}
void solve()
{
int n = ni(), a = ni(), b = ni();
double A = -1.0/(2*a);
double B = -1.0/(2*b);
double x = (A+B)/2;
double y = (n-1)*(B-A)/2;
double[] c0 = new double[]{x, y+(B-A)/2};
double[] c1 = new double[]{B, y};
double[] c2 = new double[]{A, y};
double[] res = circumcircle(inv(c0), inv(c1), inv(c2));
out.printf("%.14f\n", res[2]);
}
void run() throws Exception
{
is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
solve();
out.flush();
if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
// Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
// @Override
// public void run() {
// long s = System.currentTimeMillis();
// solve();
// out.flush();
// if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
// }
// };
// t.start();
// t.join();
}
public static void main(String[] args) throws Exception { new D().run(); }
private byte[] inbuf = new byte[1024];
public int lenbuf = 0, ptrbuf = 0;
private int readByte()
{
if(lenbuf == -1)throw new InputMismatchException();
if(ptrbuf >= lenbuf){
ptrbuf = 0;
try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
if(lenbuf <= 0)return -1;
}
return inbuf[ptrbuf++];
}
private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
private double nd() { return Double.parseDouble(ns()); }
private char nc() { return (char)skip(); }
private String ns()
{
int b = skip();
StringBuilder sb = new StringBuilder();
while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
private char[] ns(int n)
{
char[] buf = new char[n];
int b = skip(), p = 0;
while(p < n && !(isSpaceChar(b))){
buf[p++] = (char)b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}
private int[] na(int n)
{
int[] a = new int[n];
for(int i = 0;i < n;i++)a[i] = ni();
return a;
}
private long[] nal(int n)
{
long[] a = new long[n];
for(int i = 0;i < n;i++)a[i] = nl();
return a;
}
private char[][] nm(int n, int m) {
char[][] map = new char[n][];
for(int i = 0;i < n;i++)map[i] = ns(m);
return map;
}
private int[][] nmi(int n, int m) {
int[][] map = new int[n][];
for(int i = 0;i < n;i++)map[i] = na(m);
return map;
}
private int ni() { return (int)nl(); }
private long nl()
{
long num = 0;
int b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}
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