Submission #604470

#	Time	Username	Problem	Language	Result	Execution time	Memory
604470		bzhu524	Mobile (BOI12_mobile)	Java	0 / 100	337 ms	29180 KiB

mobile

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


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

        double lower = 1;
        double upper = 10e9;
        double res = upper;
        while (upper - lower >= 10e-3) {
            double mid = (upper + lower) / 2;
            double currPoint = 0;
            for (int i=0; i<n; i++) {
                long x = io.nextLong();
                long y = io.nextLong();
                double delta = Math.sqrt(mid * mid - y * y);
                double dist1 = x - delta;
                double dist2 = x + delta;

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

            if (currPoint < 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());
        }
    }
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 4
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 5
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5
• Subtask 13: 0 / 5
• Subtask 14: 0 / 5
• Subtask 15: 0 / 5
• Subtask 16: 0 / 5
• Subtask 17: 0 / 5
• Subtask 18: 0 / 5
• Subtask 19: 0 / 5
• Subtask 20: 0 / 5
• Subtask 21: 0 / 5