AtCoder Grand Contest 003 D - Anticube
解法
解説の通りにやる。
コード
import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.util.ArrayList; import java.util.Map; import java.util.NoSuchElementException; import java.util.TreeMap; /* _ooOoo_ o8888888o 88" . "88 (| -_- |) O\ = /O ____/`---'\____ .' \\| |// `. / \\||| : |||// \ / _||||| -:- |||||- \ | | \\\ - /// | | | \_| ''\---/'' | | \ .-\__ `-` ___/-. / ___`. .' /--.--\ `. . __ ."" '< `.___\_<|>_/___.' >'"". | | : `- \`.;`\ _ /`;.`/ - ` : | | \ \ `-. \_ __\ /__ _/ .-` / / ======`-.____`-.___\_____/___.-`____.-'====== `=---=' ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pass System Test! */ public class Main { private static class Task { long[] primes = Eratosthenes.getPrimes(100000); // 素数の 3 乗を含まない整数にして返す long normalize(long t) { for (long p : primes) { long p3 = p * p * p; if (p3 > t) break; while (t % p3 == 0) t /= p3; } return t; } // 素数の 3 乗を含まない整数 t との積が立方数になるような // 素数の 3 乗を含まない整数 v を返す long pair(long t) { long v = 1; for (long p : primes) { if (p * p * p > t) break; if (t % (p * p) == 0) { t /= (p * p); v *= p; } if (t % p == 0) { t /= p; v *= p * p; } } if (t != 1) { long sq = (long) Math.sqrt(t); if (sq * sq == t) v *= sq; else v *= t * t; } return v; } void solve(FastScanner in, PrintWriter out) throws Exception { int N = in.nextInt(); long[] S = new long[N]; for (int i = 0; i < N; i++) { S[i] = in.nextLong(); } TreeMap<Long, Integer> norms = new TreeMap<>(); TreeMap<Long, Long> edges = new TreeMap<>(); boolean one = false; for (long s : S) { long n = normalize(s); long p = pair(n); if (n == 1) { one = true; continue; } Integer normCount = norms.get(n); if (normCount == null) normCount = 0; norms.put(n, normCount + 1); if (!norms.containsKey(p)) norms.put(p, 0); if (n > p) { long t = n; n = p; p = t; } edges.put(n, p); } long ans = 0; for (Map.Entry<Long, Long> e : edges.entrySet()) { ans += Math.max(norms.get(e.getKey()), norms.get(e.getValue())); } if (one) ans++; out.println(ans); } public static class Eratosthenes { public static long[] getPrimes(int N) { ArrayList<Integer> primes = new ArrayList<>(); boolean[] isComposite = new boolean[N + 1]; primes.add(2); for (int i = 3; i <= N; i += 2) if (!isComposite[i]) { primes.add(i); for (int j = i * 2; j <= N; j += i) { isComposite[j] = true; } } long[] array = new long[primes.size()]; for (int i = 0; i < primes.size(); i++) { array[i] = primes.get(i); } return array; } } } /** * ここから下はテンプレートです。 */ public static void main(String[] args) throws Exception { OutputStream outputStream = System.out; FastScanner in = new FastScanner(); PrintWriter out = new PrintWriter(outputStream); Task solver = new Task(); solver.solve(in, out); out.close(); } private static class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int bufferLength = 0; private boolean hasNextByte() { if (ptr < bufferLength) { return true; } else { ptr = 0; try { bufferLength = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (bufferLength <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1; } private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126; } private void skipUnprintable() { while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; } boolean hasNext() { skipUnprintable(); return hasNextByte(); } public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } long nextLong() { if (!hasNext()) throw new NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while (true) { if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; } else if (b == -1 || !isPrintableChar(b)) { return minus ? -n : n; } else { throw new NumberFormatException(); } b = readByte(); } } double nextDouble() { return Double.parseDouble(next()); } double[] nextDoubleArray(int n) { double[] array = new double[n]; for (int i = 0; i < n; i++) { array[i] = nextDouble(); } return array; } double[][] nextDoubleMap(int n, int m) { double[][] map = new double[n][]; for (int i = 0; i < n; i++) { map[i] = nextDoubleArray(m); } return map; } public int nextInt() { return (int) nextLong(); } public int[] nextIntArray(int n) { int[] array = new int[n]; for (int i = 0; i < n; i++) array[i] = nextInt(); return array; } public long[] nextLongArray(int n) { long[] array = new long[n]; for (int i = 0; i < n; i++) array[i] = nextLong(); return array; } public String[] nextStringArray(int n) { String[] array = new String[n]; for (int i = 0; i < n; i++) array[i] = next(); return array; } public char[][] nextCharMap(int n) { char[][] array = new char[n][]; for (int i = 0; i < n; i++) array[i] = next().toCharArray(); return array; } } }