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  1. import java.io.BufferedInputStream;
  2. import java.io.InputStream;
  3. import java.io.OutputStream;
  4. import java.io.PrintWriter;
  5.  
  6. /**
  7.  * @author khokharnikunj8
  8.  */
  9.  
  10. public class Main {
  11.     public static void main(String[] args) {
  12.         new Thread(null, new Runnable() {
  13.             public void run() {
  14.                 new Main().solve();
  15.             }
  16.         }, "1", 1 << 26).start();
  17.     }
  18.  
  19.     void solve() {
  20.         InputStream inputStream = System.in;
  21.         OutputStream outputStream = System.out;
  22.         ScanReader in = new ScanReader(inputStream);
  23.         PrintWriter out = new PrintWriter(outputStream);
  24.         MAXOR solver = new MAXOR();
  25.         solver.solve(1, in, out);
  26.         out.close();
  27.     }
  28.  
  29.     static class MAXOR {
  30.         public void solve(int testNumber, ScanReader in, PrintWriter out) {
  31.             int n = in.scanInt();
  32.             int[] ar = new int[n];
  33.             for (int i = 0; i < n; i++) ar[i] = in.scanInt();
  34.             boolean[] SOSdp1 = new boolean[1 << 20];
  35.             for (int i : ar) SOSdp1[i] = true;
  36.             for (int i = 0; i < 20; ++i)
  37.                 for (int mask = 0; mask < (1 << 20); ++mask) {
  38.                     if ((mask & 1 << i) != 0)
  39.                         SOSdp1[mask ^ (1 << i)] |= SOSdp1[mask];
  40.                 }
  41.             int[] SOSdp2 = new int[1 << 20];
  42.             for (int i = 0; i < (1 << 20); i++) if (SOSdp1[i]) SOSdp2[i] = i;
  43.             for (int i = 0; i < 20; ++i)
  44.                 for (int mask = 0; mask < (1 << 20); ++mask) {
  45.                     if ((mask & 1 << i) != 0)
  46.                         SOSdp2[mask] = Math.max(SOSdp2[mask ^ (1 << i)], SOSdp2[mask]);
  47.                 }
  48.             int ans = 0;
  49.             for (int i = 0; i < n; i++) {
  50.                 ans = Math.max(ans, SOSdp2[((1 << 20) - 1) ^ ar[i]] | ar[i]);
  51.             }
  52.             out.println(ans);
  53.  
  54.  
  55.         }
  56.  
  57.     }
  58.  
  59.     static class ScanReader {
  60.         private byte[] buf = new byte[4 * 1024];
  61.         private int index;
  62.         private BufferedInputStream in;
  63.         private int total;
  64.  
  65.         public ScanReader(InputStream inputStream) {
  66.             in = new BufferedInputStream(inputStream);
  67.         }
  68.  
  69.         private int scan() {
  70.             if (index >= total) {
  71.                 index = 0;
  72.                 try {
  73.                     total = in.read(buf);
  74.                 } catch (Exception e) {
  75.                     e.printStackTrace();
  76.                 }
  77.                 if (total <= 0) return -1;
  78.             }
  79.             return buf[index++];
  80.         }
  81.  
  82.         public int scanInt() {
  83.             int integer = 0;
  84.             int n = scan();
  85.             while (isWhiteSpace(n)) n = scan();
  86.             int neg = 1;
  87.             if (n == '-') {
  88.                 neg = -1;
  89.                 n = scan();
  90.             }
  91.             while (!isWhiteSpace(n)) {
  92.                 if (n >= '0' && n <= '9') {
  93.                     integer *= 10;
  94.                     integer += n - '0';
  95.                     n = scan();
  96.                 }
  97.             }
  98.             return neg * integer;
  99.         }
  100.  
  101.         private boolean isWhiteSpace(int n) {
  102.             if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1) return true;
  103.             else return false;
  104.         }
  105.  
  106.     }
  107. }
  108.  
  109.  
Success #stdin #stdout 0.18s 39452KB
comments (?)
stdin 
5
9 8 1 6 2
stdout 
15
https://ideone.com/DO2A2a
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

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