Submission #604447

#	Time	Username	Problem	Language	Result	Execution time	Memory
604447		bzhu524	Mobile (BOI12_mobile)	Java	Compilation error	0 ms	0 KiB

mobile

import java.util.*;
import java.io.*;


public class MobileBalticOI {
    public static void main(String[] args) {
        FastIO io = new FastIO();
        int n = io.nextInt();
        int len = io.nextInt();
        long[][] points = new long[n][n];

        for (int i=0; i<n; i++) {
            long x = io.nextLong();
            long y = io.nextLong();
            points[i][0] = x;
            points[i][1] = y;
        }

        double lower = 1;
        double upper = 10e9;
        double res = Double.MAX_VALUE;

        while (upper - lower >= 10e-4) {

            double mid = (upper + lower) / 2;
            double curr = 0;
            for (int i=0; i<n; i++) {

                long x = points[i][0];
                long y = points[i][1];
                double delta = Math.sqrt(mid * mid - y * y);
                double dist1 = x - delta;
                double dist2 = x + delta;

                if (dist1 <= curr) {
                    curr = Math.max(curr, dist2);
                }
            }

            if (curr < len) {
                lower = mid;
            } else {
                upper = mid;
                res = Math.min(res, mid);
            }
        }

        String r = String.format("%.6f", res);
        System.out.println(r);
    }

    static class FastIO extends PrintWriter {
        private InputStream stream;
        private byte[] buf = new byte[1<<16];
        private int curChar, numChars;

        // standard input
        public FastIO() { this(System.in,System.out); }
        public FastIO(InputStream i, OutputStream o) {
            super(o);
            stream = i;
        }
        // file input
        public FastIO(String i, String o) throws IOException {
            super(new FileWriter(o));
            stream = new FileInputStream(i);
        }

        // throws InputMismatchException() if previously detected end of file
        private int nextByte() {
            if (numChars == -1) throw new InputMismatchException();
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars == -1) return -1; // end of file
            }
            return buf[curChar++];
        }

        // to read in entire lines, replace c <= ' '
        // with a function that checks whether c is a line break
        public String next() {
            int c; do { c = nextByte(); } while (c <= ' ');
            StringBuilder res = new StringBuilder();
            do { res.appendCodePoint(c); c = nextByte(); } while (c > ' ');
            return res.toString();
        }
        public int nextInt() { // nextLong() would be implemented similarly
            int c; do { c = nextByte(); } while (c <= ' ');
            int sgn = 1; if (c == '-') { sgn = -1; c = nextByte(); }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res = 10*res+c-'0';
                c = nextByte();
            } while (c > ' ');
            return res * sgn;
        }
        public double nextDouble() { return Double.parseDouble(next()); }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}

Compilation message (stderr)

mobile.java:5: error: class MobileBalticOI is public, should be declared in a file named MobileBalticOI.java
public class MobileBalticOI {
       ^
1 error