結果

問題 No.3156 Count That Day's N
コンテスト
ユーザー tenten
提出日時 2025-06-02 18:13:00
言語 Java
(openjdk 23)
結果
AC  
実行時間 181 ms / 3,000 ms
コード長 4,455 bytes
コンパイル時間 4,274 ms
コンパイル使用メモリ 90,824 KB
実行使用メモリ 46,788 KB
最終ジャッジ日時 2025-06-02 18:13:11
合計ジャッジ時間 9,287 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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
sample AC * 4
other AC * 32
権限があれば一括ダウンロードができます

ソースコード

diff # 

import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner();
        long k = sc.nextLong();
        long n = sc.nextLong();
        Map<Long, List<Long>> six = new HashMap<>();
        for (long i = 1; i * i * i * i * i * i < n; i++) {
            long v = i * i * i * i * i * i;
            long mod = v % k;
            if (!six.containsKey(mod)) {
                six.put(mod, new ArrayList<>());
            }
            six.get(mod).add(v);
        }
        Map<Long, List<Long>> four = new HashMap<>();
        for (long i = 1; i * i * i * i < n; i++) {
            long v = i * i * i * i;
            long mod = v % k;
            if (!four.containsKey(mod)) {
                four.put(mod, new ArrayList<>());
            }
            four.get(mod).add(v);
        }
        Set<Long> ans = new HashSet<>();
        for (long x : six.keySet()) {
            if (!four.containsKey((k - x) % k)) {
                continue;
            }
            List<Long> a = six.get(x);
            List<Long> b = four.get((k - x) % k);
            for (long y : a) {
                for (long z : b) {
                    if (y + z > n) {
                        break;
                    }
                    if (isSqrt((y + z) / k)) {
                        ans.add(y + z);
                    }
                }
            }
        }
        System.out.println(ans.size());
    }
    
    static boolean isSqrt(long x) {
        long left = 0;
        long right = Integer.MAX_VALUE / 2;
        while (right - left > 1) {
            long m = (left + right) / 2;
            if (m * m <= x) {
                left = m;
            } else {
                right = m;
            }
        }
        return left * left == x;
    }
}

class FastScanner {
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;
    private static final int BUFFER_SIZE = 1 << 16; // 65,536 バイト

    public FastScanner() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    private byte read() {
        try {
            if (bufferPointer == bytesRead) {
                bytesRead = din.read(buffer, 0, BUFFER_SIZE);
                if (bytesRead == -1) return -1;
                bufferPointer = 0;
            }
            return buffer[bufferPointer++];
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String next() {
        byte b = read();
        // 空白文字を読み飛ばす
        while (isSpaceChar(b)) {
            b = read();
        }
        StringBuilder sb = new StringBuilder();
        while (!isSpaceChar(b)) {
            sb.append((char) b);
            b = read();
        }
        return sb.toString();
    }

    public int nextInt() {
        int ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public long nextLong() {
        long ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10L + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public double nextDouble() {
        double ret = 0, div = 1;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c) && c != '.');
        if (c == '.') {
            while (!isSpaceChar(c = read())) {
                ret += (c - '0') / (div *= 10);
            }
        }
        return neg ? -ret : ret;
    }

    private boolean isSpaceChar(byte c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public void close() {
        try {
            if (din != null) din.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}
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