RUCP2016 Day3 B 周期数列 - Periodic Sequence -
考察
考えられる周期tをそれぞれ試していくだけ
N = ktから,tはNを割り切る数なのでそこまで多くない
ソースコード
import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.ArrayList; import java.util.NoSuchElementException; public class Main implements Runnable{ int N; int[] S; public void solve() { N = nextInt(); S = new int[N]; for(int i = 0;i < N;i++){ S[i] = nextInt(); } ArrayList<Integer> ts = new ArrayList<Integer>(); for(int i = 1;i <= N;i++){ if(N%i==0){ ts.add(i); } } int ans = 0; for(int t : ts){ int k = N / t; boolean flag = false; for(int i = 0;i < t;i++){ for(int j = 0;j < k;j++){ if(S[j * t + i]==S[i])continue; flag = true; break; } if(flag)break; } if(!flag){ ans = Math.max(ans, k); } } out.println(ans); } public static void main(String[] args) { new Thread(null,new Main(),"",32 * 1024 * 1024).start(); } /* Input */ private static final InputStream in = System.in; private static final PrintWriter out = new PrintWriter(System.out); private final byte[] buffer = new byte[2048]; private int p = 0; private int buflen = 0; private boolean hasNextByte() { if (p < buflen) return true; p = 0; try { buflen = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (buflen <= 0) return false; return true; } public boolean hasNext() { while (hasNextByte() && !isPrint(buffer[p])) { p++; } return hasNextByte(); } private boolean isPrint(int ch) { if (ch >= '!' && ch <= '~') return true; return false; } private int nextByte() { if (!hasNextByte()) return -1; return buffer[p++]; } public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = -1; while (isPrint((b = nextByte()))) { sb.appendCodePoint(b); } return sb.toString(); } public int nextInt() { return Integer.parseInt(next()); } public long nextLong() { return Long.parseLong(next()); } public double nextDouble() { return Double.parseDouble(next()); } @Override public void run() { out.flush(); new Main().solve(); out.close(); } }