結果

問題 No.328 きれいな連立方程式
ユーザー uwi
提出日時 2015-12-21 23:18:35
言語 Java
(openjdk 23)
結果
AC  
実行時間 52 ms / 2,000 ms
コード長 4,858 bytes
コンパイル時間 4,302 ms
コンパイル使用メモリ 86,632 KB
実行使用メモリ 50,364 KB
最終ジャッジ日時 2024-09-18 18:10:47
合計ジャッジ時間 5,914 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
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ファイルパターン 結果
other AC * 31
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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 contest;
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 Q703 {
    InputStream is;
    PrintWriter out;
    String INPUT = "";
    
    void solve()
    {
        long c1 = ni();
        long c2 = ni();
        long c3 = ni();
        long c4 = ni();
        if(c1 == 0){
            out.println("R");
            return;
        }
        // c3=c1((c2/c1)^2-b^2)
        // b^2=(c2/c1)^2-c3/c1 ?
        // c4=c1((c2/c1)^3-3(c2/c1)b^2)
        // 3(c2/c1)b^2=(c2/c1)^3-c4/c1
        // b^2=(c2/c1)^2/3-c4/3c2
        F a = new F(c4*c1-c3*c2, 2*(c3*c1-c2*c2));
//          F br = F.mul(a, new F(c1)).sub(new F(c2)).div(new F(2));
        F b2 = F.mul(a, a);
        b2.sub(new F(2).mul(a).mul(F.sub(a, new F(c2, c1))));
        b2.sub(new F(c3, c1));
        if(b2.num > 0){
            out.println("I");
        }else{
            out.println("R");
        }
    }
    
    public static class F implements Comparable<F> {
        public long num, den;
        
        public F(){ this.num = 0; this.den = 1; }
        public F(long num){ this.num = num; this.den = 1;}
        public F(long num, long den){ this.num = num; this.den = den; reduce();}
        
        public F reduce()
        {
            if(den == 0) {
            }else if(num == 0) {
                den = 1;
            }else {
                if(den < 0) {
                    num = -num;
                    den = -den;
                }
                long g = gcd(Math.abs(num), den);
                num /= g;
                den /= g;
            }
            return this;
        }
        
        public static F add(F a, F b){ return new F(a.num*b.den+a.den*b.num, a.den*b.den); }
        public static F sub(F a, F b){ return new F(a.num*b.den-a.den*b.num, a.den*b.den); }
        public static F mul(F a, F b){ return new F(a.num*b.num, a.den*b.den); }
        public static F div(F a, F b){ return new F(a.num*b.den, a.den*b.num); }
        public static F inv(F a){ return new F(a.den, a.num); }
        
        public F add(F b){ num = num*b.den+den*b.num; den *= b.den; return reduce(); }
        public F sub(F b){ num = num*b.den-den*b.num; den *= b.den; return reduce(); }
        public F mul(F b){ num *= b.num; den *= b.den; return reduce(); }
        public F div(F b){ num *= b.den; den *= b.num; return reduce(); }
        public F inv(){ long d = num; num = den; den = d; return reduce(); }
        
        protected static long gcd(long a, long b) {
            while (b > 0) {
                long c = a;
                a = b;
                b = c % b;
            }
            return a;
        }
        
        public String toString() { return num + "/" + den; }
        public int compareTo(F f) { return Long.signum(num * f.den - f.num * den); }
    }
    
    
    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");
    }
    
    public static void main(String[] args) throws Exception { new Q703().run(); }
    
    private byte[] inbuf = new byte[1024];
    private 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 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[] na(int n)
    {
        int[] a = new int[n];
        for(int i = 0;i < n;i++)a[i] = ni();
        return a;
    }
    
    private int ni()
    {
        int num = 0, 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 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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