結果
問題 | No.724 円と円の間の円 |
ユーザー |
|
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 |
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ファイルパターン | 結果 |
---|---|
other | AC * 24 |
ソースコード
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)^2public 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はなまぬるいかも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)); }}